Monotonicity of the Yamabe invariant under connect sum over the boundary
|
|
- Nicholas Garrison
- 5 years ago
- Views:
Transcription
1 Ann Glob Anal Geom (2009) 35: DOI /s ORIGINAL PAPER Monotonicity of the Yamabe invariant under connect sum over the boundary Fernando Schwartz Received: 6 June 2008 / Accepted: 18 August 2008 / Published online: 5 September 2008 SpringerScience+BusinessMediaB.V.2008 Abstract We show that the Yamabe invariant of manifolds with boundary satisfies a monotonicity property with respect to connected sums along the boundary, similar to the one in the closed case. A consequence of our result is that handlebodies have maximal invariant. Keywords Manifold with boundary Positive scalar curvature Yamabe invariant 1 Introduction, main results, and sketch of proof The Yamabe invariant of a closed manifold is a smooth invariant. It is a minimax of the total scalar curvature functional over the space of unit volume metrics on the manifold. More precisely, one computes the infimum of the functional over a fixed conformal class, and then the supremum of the infimums is computed over the set of all conformal classes. The Yamabe invariant has been extensively studied. It is known that whenever the minimax is achieved the manifold admits an Einstein metric, which is an important question in geometry. When the invariant is positive it is very difficult to determine whether it is achieved or not. Furthermore, very few invariants have been computed in the positive case. The analysis of the Yamabe invariant can also be carried out in the realm of manifolds with boundary. The corresponding quantity to study is a quotient of the energy, which in this case is the total scalar curvature plus the total mean curvature of the boundary, divided by a normalization term. Since one can choose to normalize with respect to the total volume of the manifold or the total area of its boundary, two possible definitions for the invariant appear. F. Schwartz (B) Mathematics Department, Duke University, Durham, NC 27710, USA fernando@math.duke.edu Present Address: F. Schwartz Mathematics Institute, Zeeman Building, University of Warwick, Coventry CV4 7AL, UK
2 116 Ann Glob Anal Geom (2009) 35: Let (M n, g) be a compact manifold with boundary. Proceeding in analogy with the closed case, we define the (conformally invariant) Yamabe constant of (M, g) by E( g) Y λ (M, [g]) = inf g [g] N λ ( g), (1) where E( g) is the energy of the metric g and λ {0, 1} determines whether the normalization N λ is with respect to the volume of g (λ = 1) or the area of the boundary of g (λ = 0). It is a well known fact that Y λ (M n, [g]) Y λ (S n +, [g 0]), whereg 0 denotes the round metric on the hemisphere. Existence of minimizers of the above quotient have been studied by Escobar in [5,6], where he proved that solutions exist in most cases (See also [4,9,10]). A standard argument shows that, when writing Eq. 1 in terms of conformal factors of conformally related metrics (see Eqs. 5, 6), solutions of the Euler-Lagrange equations correspond to conformally related metrics that solve the Yamabe problem on (M, g). This is, conformal metrics with constant scalar curvature and minimal boundary (in the case λ = 1), and scalar flat metrics with boundary having constant mean curvature (whenever λ = 0). The Yamabe invariant of a smooth manifold with boundary is defined as σ λ (M) = sup Y λ (M, [g]), (2) [g] C where C is the set of all smooth conformal classes of metrics on M. From the considerations above it follows that < σ λ (M n ) σ λ (S n + ). In this paper we prove the following result. Theorem 1.1 Let M 1, M 2 be smooth n-manifolds with boundary, n 3.LetM 1 #M 2 denote their connected sum along the boundary. Then, for λ {0, 1}, σ λ (M 1 #M 2 ) σ λ (M 1 M 2 ), (3) where M 1 M 2 denotes the disjoint union of M 1, M 2 and { σ λ (M 1 M 2 ) = ( σ λ (M 1 ) n 2 + σ λ (M 2 ) n 2 ) n 2 σ λ (M 1 ), σ λ (M 2 ) 0, min{σ λ (M 1 ), σ λ (M 2 )} otherwise. (4) Our result is an extension, to manifolds with boundary, of Kobayashi s classical theorem about monotonicity of the Yamabe invariant over connect sums of closed manifolds [8]. The proof of our result parallels his proof with the added boundary ingredients, plus some approximation results that are adaptations of some found by Akutagawa and Botvinnik [1]. An interesting consequence of our result is the following corollary. Corollary 1.2 Handlebodies have maximal invariant. This is, if H n is the result of attaching a finite number of handles to the n-ball, then σ λ (H) = σ λ (S+ n ), λ {0, 1}. Sketch of the Proof of Theorem 1.1 The proof of the theorem is divided into two cases: (a) when the Yamabe invariant of both M 1 and M 2 is positive, and (b) when one of the invariants is nonpositive. The idea behind the proof of (a) is to show that if both M 1, M 2 have positive metrics, then after gluing a long enough handle over the boundary of M 1 M 2 one obtains a manifold whose Yamabe constant is larger than the Yamabe constant of M 1 M 2 minus a small error. Therefore, the invariant of M 1 #M 2 is no less than the invariant of M 1 M 2. To prove (b) we endow M 1 and M 2 with some particular negative metrics, which
3 Ann Glob Anal Geom (2009) 35: can be done by a classic result of Kazdan and Warner. Using some approximation lemmas (found in the appendix) we prove that the Yamabe constant of the connect sum is bounded below by the appropriate quantities in terms of the Yamabe constants of M 1 and M 2. 2Preliminaries Let (M n, g) be a Riemannian manifold of dimension n 3. The energy of u C (M) with respect to g is defined as E g (u) = M ( g u 2 + n 2 ) 4(n 1) R gu 2 dv g + n 2 h g u 2 da g. (5) 2 M Using the transformation laws for the scalar curvature and the mean curvature, it is standard to note that the energy of u is the total scalar curvature plus the total mean curvature of the conformally related metric g = u 4/(n 2) g,i.e.,e g (u) = E( g) = M R gdv + n 2 2 M h gda. For λ {0, 1}, the normalization factor is just ( N g,λ (u) = λ u n 2 2n dv g + (1 λ) M M ) n u 2(n 1) n 1 n 2 da g, (6) It follows that N g,λ (u) = N λ ( g) = λvol(m, g)+(1 λ)(area( M, g) n/(n 1) ), as desired. This way, we get that Y λ (M, [g]) = inf { Eg (u) inf } { N g,0 (u) : u 0 on M } Eg (u) N g,1 (u) : u 0 on M if λ = 0, if λ = 1. Outline of the Proof of Theorem 1.1 The simple argument below shows how Eq. 4 of the theorem is satisfied. The proof of Eq. 3 is split into two cases. In Sect. 3 we deal with the case when both σ λ (M 1 ) and σ λ (M 2 ) are positive, where we prove that Eq. 3 follows from the (more general) Handle Monotonicity Theorem (Theorem 3.1). In Sect. 4 we study the case when at least one of σ λ (M 1 ), σ λ (M 2 ) is nonpositive. In Sects. 3 and 4 we use a series of approximation arguments. These are modifications of the approximation lemmas that appear in Kobayashi s original paper [8]andAkutagawa and Botvinnik s paper [1]. We include their proofs, for sake of completeness, in the Appendix. Lemma 2.1 Let λ {0, 1} and (M 1, g 1 ), (M 2, g 2 ) be Riemannian manifolds with boundary. The following holds: Y λ (M 1 M 2, g 1 g 2 ) { = ( Y λ (M 1, g 1 ) n 2 + Y λ (M 2, g 2 ) n 2 ) n 2 Y λ (M 1, g 1 ), Y λ (M 2, g 2 ) 0, min{y λ (M 1, g 1 ), Y λ (M 2, g 2 )} otherwise.
4 118 Ann Glob Anal Geom (2009) 35: Proof Write E 1 (u), V 1 (u) and E 2 (u), V 2 (u) for the expressions in Eqs. 5 and 6 integrated over M 1, M 1 and M 2, M 2, respectively. We have that Y λ (M 1 M 2, g 1 g 2 ) = inf { E 1 (u) + E 2 (u) : u C 1 ( M) with V 1 (u) + V 2 (u) = 1 } { } = inf V 1 (u) n 2 E 1 (u) n + V V 1 (u) n 2 2 (u) n 2 E 1 (u) n : V n V 1 (u) n 2 1 (u) + V 2 (u) = 1 n } = inf {α n 2 n Yλ (M 1, g 1 ) + (1 α) n 2 n Yλ (M 2, g 2 ) : 0 α 1 = { ( Y λ (M 1, g 1 ) n 2 + Y λ (M 2, g 2 ) n 2 ) n 2 Y λ (M 1, g 1 ), Y λ (M 2, g 2 ) 0, min{y λ (M 1, g 1 ), Y λ (M 2, g 2 )} otherwise. As a direct consequence of the lemma is the proof of Eq. 4. Corollary 2.2 Let M1 n, Mn 2, n 3 be Riemannian manifolds with boundary. The following holds: σ λ (M 1 M 2 ) = { ( σ λ (M 1 ) n 2 + σ λ (M 2 ) n 2 ) n 2 σ λ (M 1 ), σ λ (M 2 ) 0, min{σ λ (M 1 ), σ λ (M 2 )} otherwise. 3Proofofthepositivecase The proof of Theorem 1.1 is split in two cases: the positive case, which we present here, and the nonpositive case (where at least one of σ λ (M 1 ), σ λ (M 2 ) is nonpositive), which we prove in Sect. 4 below. Throughout this section we assume that M 1, M 2 are n-dimensional, compact manifolds with boundary (n 3) with positive Yamabe invariant. We actually prove here a more general theorem, valid only for the positive case. We show that the Yamabe invariant is monotonic when attaching a handle over the boundary. In particular, from this it follows that all handlebodies have maximal Yamabe invariant. Theorem 3.1 (Handle monotonicity) Let M be a compact manifold with boundary and positive Yamabe invariant (σ λ (M) >0). Denote by M the manifold obtained by attaching a handle to the boundary of M. Then σ λ ( M) σ λ (M). The handle monotonicity theorem has two immediate consequences. Proof of Theorem 1.1 in the Positive Case Assuming that σ λ (M 1 ), σ λ (M 2 ) > 0, apply Theorem 3.1 to M 1 M 2 when attaching a handle between a boundary component of M 1 and a boundary component of M 2.TogetherwithCorollary2.2 this gives σ λ (M 1 #M 2 ) σ λ (M 1 M 2 ) = min{σ λ (M 1 ), σ λ (M 2 )}. Proof of Corollary 1.2 Use the Handle monotonicity theorem on B n, taking into consideration that σ λ ( B n ) = σ λ (S+ n ) is maximal.
5 Ann Glob Anal Geom (2009) 35: We now give the proof of the main theorem of this section. Proof of Theorem 3.1 Fix ɛ > 0small.Letg be a metric on M so that 0 < Y λ (M) ɛ < Y λ (M, g ). Pick p 1, p 2 M.ByLemmaA.8 there is a metric g close to g so that in a neighborhood of p 1 and p 2, g is isometric to a fixed neighborhood B λ (q, ɛ ) of q Sλ n,forsomeɛ > 0. The Lemma also gives that R g 0 on M. There exists a function λ C (M {p 1, p 2 }) which is 1 outside B λ (q, ɛ /2) and such that the metric g = e λ g is isometric to the half infinite cylinder [0, ) S+ n 1 around the removed points. For convenience we write (M {p 1, p 2 }, g) =[0, ) S n 1 + ( M, g) [0, ) S n 1 +, where M is the complement of the two cylinders. We glue ( M, g) with [0, l] S+ n 1 to get a smooth Riemannian manifold ( M, g l ). This is, M is the result of attaching a handle on M connecting neighborhoods of p 1 and p 2.We have the follwing decomposition: ( M, g l ) = ( M, g) [0, l] S n 1 +. (7) Since Y λ ( M, g l ) = inf u M ( u 2 + ( λ 2n M u n 2 dv gl + (1 λ) 4(n 1) n 2 R g l u 2 )dv gl + n 2 2 ( M M h g l u 2 da gl ) n 2(n 1) n 1 u n 2 da gl ) n 2 n we can take a positive function u l C ( M) such that ( u l 2 + R gl ul 2 )dv g l + n 2 h gl ul 2 M 2 dσ l < Y λ ( M, g l ) + 1 M 1 + l (8) and ( λ u l n 2 2n dv gl + (1 λ) M M ) n u l 2(n 1) n 1 n 2 da gl = 1. (9) Lemma 3.2 There exists a section, say {t l } S+ n 1 in the cylindrical part of M (see Eq.7) such that {t l } S n 1 + where A is a constant independent of l. Proof Let ( u l 2 + ul 2 )dv l + u 2 {t l } S n 2 l da l < A l, A = min{0, min h g (x)}area( M, g) n 1 1 min{0, min R g (x)}vol( M, g) n 2. x M x M
6 120 Ann Glob Anal Geom (2009) 35: Using Hölder s inequality on (8) andthefactthatr gl 0 outside the cylindrical part of M we get ( u l 2 + n 1 ) dv [0,l] S n 1 + 4(n 2) (n 1)(n 2)u2 l +(n 2)(n 3) u 2 [0,l] S n 2 l da < Y λ ( M, g l ) l + A. This way, there is a t l [0, l] such that ( u l 2 + n 1 {t l } S+ n 1 4(n 2) (n 1)(n 2)u2 l ( < Y λ ( M, g l ) + 1 ) /l. 1 + l + A ) dv + (n 2)(n 3) u 2 {t l } S n 2 l da This proves Lemma 3.2. We continue with the proof of Theorem 3.1 as follows: cut off M on the section {t l } S+ n 1 and attach two half-infinite cylinders to it, so (M {p 1, p 2 }, g) reappears. This time we write it as (M {p 1, p 2 }, g) =[0, ) S n 1 + ( M {t l } S n 1 +, g l) [0, ) S n 1 +. We think of u l as defined on M {t l } S n 1 + and extend it to the whole space M {p 1, p 2 } as follows: Let U l be a Lipschitz function on M {p 1, p 2 } such that and U l (t, x) = where ũ l = u l {tl } S+ n 1 M {p 1,p 2 } U l = u l on M {t l } S n 1 + { (1 t)ũl (x) for (t, x) [0, 1] S n for (t, x) [1, ) S n 1 + C (S+ n 1 ).Nowitiseasytoseefrom(8) and Lemma 3.2 that ( U l 2 + n 1 4(n 2) R gu l 2 )dv g + n 2 2 where B is a constant independent of l.fromeq.9 it follows that ( λ U l n 2 2n dv gl + (1 λ) M M Therefore, we have M {p inf 1,p 2 } ( U 2 + U (λ 2n M {p1,p2 } U n 2 dv g + (1 λ)( M σ λ ( M), M h g U 2 l da g < Y λ ( M, g l ) + B l, ) n U l 2(n 1) n 1 n 2 da gl > 1. 4(n 2) n 1 R gu 2 )dv g + n 2 2 M h gu 2 da g 2(n 1) U n 2 da g ) n 1 n ) (n 2) n (10)
7 Ann Glob Anal Geom (2009) 35: where the infimum is taken over all non-negative Lipschitz functions U with compact support. It follows from the choice of the metric g that the left side of Eq. 10 is equal to Y λ (M, g).sinceɛ was arbitrary we conclude σ λ (M) σ λ ( M),whichcompletestheproofof Theorem Proofofthenonpositivecase In this section we give a proof of Theorem 1.1 whenever one of σ λ (M 1 ), σ λ (M 2 ) is nonpositive. We first prove some lemmas. Lemma 4.1 Let (M n, g ), n 3 be a compact manifold with boundary. Suppose that < Y λ (M, g ) 0. Then the following holds: (λ = 1) The scalar curvature R g of a metric g [g ] with h g 0 satisfies n 2 4(n 1) (min R g)vol(m, g) 2/n Y 1 (M, g), and equality above implies that R g is a constant. (λ = 0) The mean curvature h g of a metric g [g ] with R g 0 satisfies n 2 (min h g )Area( M, g) 1/(n 1) Y 0 (M, g ), 2 where equality above implies that h g is a constant. Proof We first prove the case λ = 1. Let g [g ] with h g 0. A standard argument (c.f. [3]) shows that, since h g 0 we must have min R g 0, or else Y (M, [g ])>0. This way, Y 1 (M, [g M ]) = inf ( u 2 + 4(n 1) n 2 R gu 2 )dv g + n 2 2 M h gu 2 dσ u 0 in M ( M u2n/(n 2) dσ ) (n 2)/n n 2 4(n 1) inf u 0 in M (min R g ) M u2 dv g ( M u2n/(n 2) dσ ) (n 2)/n n 2 4(n 1) (min R g)vol(m, g) 2/n. The last line holds by Hölder s inequality. If this inequality were an equality, take a sequence {u n } so that (E g (u n )/N g,1 (u n )) Y 1 (M, [g ]).Then{u n } also converges to the infimum of M n 2 4(n 1) R gu 2 dv g (,andso u M u2n/(n 2) dσ ) (n 2)/n n 2 0. We deduce that min R g = ( M R g)/vol(m, g), which in turn implies that R g is constant. Proof of the case λ = 0. Let g [g ] with R g 0. A similar argument as the one above gives that min h g 0. This way, Y 0 (M, [g]) = inf u 0 on M n 2 2 M ( u 2 + inf u 0 on M 4(n 1) n 2 R gu 2 )dv g + n 2 2 M h gu 2 dσ ( M u2(n 1)/(n 2) dσ ) (n 2)/(n 1) (min h g ) M u2 dσ ( M u2(n 1)/(n 2) dσ ) (n 2)/(n 1) n 2 (min h g )Area( M, g) 1/(n 1). 2
8 122 Ann Glob Anal Geom (2009) 35: The last line is obtained by Hölder s inequality. The case of equality is similar to the cases of equality when λ = 1. The following is a well-known result of Escobar [5,6] which parallels that of Aubin [2] for the closed case. Theorem 4.2 Let (M n, g), n 3 be a compact manifold with boundary. If < Y λ (M, [g]) <Y λ (B n, [g 0 ]), then the infimum is achieved at a Yamabe metric. This is, (λ = 1) There exists a function u C (M) with E g (u)/n g,1 (u) = Y 1 (M, [g]), andthe metric g = u 4/(n 2) ghaszeromeancurvatureh g 0 and constant scalar curvature R g = Y 1 (M, [g])vol(m, g) 2/n. (λ = 0) There exists a function u C (M) with E g (u)/n g,0 (u) = Y 0 (M, [g]), so that the metric g = u 4/(n 2) ghaszeroscalarcurvaturer g 0 and constant mean curvature h g = Y 0 (M, [g])area( M, g) 1/(n 1). A direct consequence of the above theorem together with Lemma 4.1 is the following result. Corollary 4.3 Consider (M, g ) with < Y λ (M, [g ]) 0. Then (λ = 1) (λ = 0) max (min R g)vol(m, g) 2/n = Y 1 (M, [g ]). {g [g ]:h g 0} In particular, if σ 1 (M) 0, wegetthat sup (min R g )Vol(M, g) 2/n = Y 1 (M). {g : g [g ], h g 0, [g ] C} max (min h g)area( M, g) 1/(n 1) = Y 0 (M, [g ]). {g [g ]:R g 0} In particular, if σ 0 (M) 0, wegetthat sup (min h g )Area( M, g) 1/(n 1) = Y 0 (M). {g : g [g ], R g 0, [g ] C} Proof of Theorem 1.1 in the Nonpositive Case We first prove the case λ = 1. For a real number a R, leta denote the negative part of a. Thisisa = max{ a, 0}. By Kazdan and Warner s Theorem [7] therearemetricsg 1, g 2 on M 1, M 2, respectively, such that min R g1 = min R g2 = ((Y 1 (M 1 ) ) n/2 + (Y 1 (M 2 ) ) n/2 + 2ɛ) 2/n, R g1 (p 1 ) = R g2 (p 2 ) = n(n 1) at some points p i M i, h gi 0 on M i, (Y Vol(M i, g i ) = 1 (M i ) ) n/2 +ɛ for i = 1, 2 (Y 1 (M 1 ) ) n/2 +(Y 1 (M 2 ) ) n/2 +2ɛ where ɛ > 0isanarbitrarynumber.ByLemmaA.10 there exists a metric g of M 1 #M 2 such that h g 0, min R g = ((Y 1 (M 1 ) ) n/2 + (Y (M 2 ) ) n/2 + 2ɛ) 2/n,
9 Ann Glob Anal Geom (2009) 35: and Hence, from Corollary 4.3 we get Vol(M 1 #M 2, g) <1 + ɛ. Y 1 (M 1 #M 2 ) ((Y 1 (M 1 ) ) n/2 + (Y 1 (M 2 ) ) n/2 ) 2/n, which ends the proof of the first case. Proof of the case λ = 0. Let g i be metrics on M i, i = 1, 2 such that min h g1 = min h g2 = ((Y (M 1 ) ) n 1 + (Y (M 2 ) ) n 1 + 2ɛ) 1/(n 1), R gi 0 in M i, h gi (p i ) 0, R gi (p i ) = n(n 1), at some points p i M i, i = 1, 2 (Y (M Area( M i, g i ) = i ) ) n 1 +ɛ for i = 1, 2 (Y (M 1 ) ) n 1 +(Y (M 2 ) ) n 1 +2ɛ where ɛ is an arbitrary positive number. By Lemma A.10 there exists a metric g on M 1 #M 2 such that and R g 0, min h g = ((Y 0 (M 1 ) ) n 1 + (Y 0 (M 2 ) ) n 1 + 2ɛ) 1/(n 1) Hence, from Corollary 4.3 we get Area(M 1 #M 2, g) <1 + ɛ. Y 0 (M 1 #M 2 ) ((Y 0 (M 1 ) ) n 1 + (Y 0 (M 2 ) ) n 1 ) 1/(n 1). This ends the proof of the nonpositive case of Theorem 1.1. Acknowledgements This work was partially supported by NSF grant # DMS Appendix A: Approximation lemmas This section consists of several approximation lemmas. The results are, essentially, adaptations of those found in Kobayashi [8] and Akutagawa and Botvinnik [1] to fit our scenario. We include the more relevant proofs here. Lemma 4.4 For any δ > 0 there exists a smooth non-negative function 0 w δ 1 and a positive constant ɛ(δ), 0 < ɛ(δ) < δ, such that (i) w δ (t) [0,ɛ(δ)] 1, w δ (t) [δ, ) 0, (ii) tẇ δ (t) < δ for t 0, (iii) t 2 ẅ δ (t) < δ for t 0. Proof Elementary. Lemma 4.5 Let ḡ, g be two Riemannian metrics on M and h = g ḡ. Then R g Rḡ = Pḡ(h) + Qḡ(h), where Pḡ(h) = ḡ(trḡh) + i j h ij h, Ricḡ ḡ, Qḡ(h) c( h 2 q 3 + h h 2 q 2 + ( h h 2 + Ricḡ h 2 )q). Here, c = c(n) >0 is a constant that depends only on the dimension n of M, and q is a non-negative smooth function that satisfies q g ḡ.
10 124 Ann Glob Anal Geom (2009) 35: Proof Astraightforwardcalculationofwritingoutthescalarcurvatureintermsofthemetric and its derivatives that can be found in [8]. Lemma 4.6 (Fermi coordinates) Let (M n, g), n 3 be a compact Riemannian manifold with boundary and o M. There exists Fermi coordinates around o. This is, coordinates (r, x) around o so that γ x (r) = (r, x) is a geodesic and the set {(0, x) : x} corresponds to Mnearo.Wehave (i) g 00 = g( r, r ) = 1, g 00 = r g 00 = 0, (ii) g 0i = 0, g 0i = r g 0i = 0 for i > 0, (iii) g ij = (g M ) ij, g ij = 2A ij, i, j > 0. Proposition A.4 Let o M and ḡ, g be metrics on M such that Rḡ(o) = R g (o) and jo 1ḡ = j o 1 g (i.e.,ḡand g coincide up to first order derivatives on o). Consider Fermi coordinates around o as in Lemma 4.6. Thenthefamilyofmetrics has the following properties: (i) g δ =ḡ outside B δ (o), (ii) g δ = gonb ɛ(δ) (o), (iii) h gδ = h g on B ɛ(δ) (o), (iv) g δ ginc 1 (M) as δ 0, (v) R gδ Rḡ in C 0 (M) as δ 0, (vi) h gδ h g in C 0 ( M) as δ 0. g δ =ḡ + w δ (r)( g ḡ) Proof The proof of this proposition is similar to Kobayashi s Theorem (Lemma 3.2 of [8]). We proceed as follows: (i) and (ii) are direct and (iii) follows from (ii). Toprove(iv) consider the function w δ from Lemma 4.4.Notethatw δ is supported inside [0, δ].thisway g δ ḡ = w δ (r)( g ḡ) = O(r 2 ), and so g δ ḡ in C 0 (M). TogettheC 1 (M) convergence we see that ( g δ ḡ) = ẇ δ (r)( g ḡ) + w δ (r) ( g ḡ). Since g ḡ = O(r 2 ) and ( g ḡ) = O(r),Lemma4.4 implies g δ ḡ ẇ δ (r)r O(r 2 ) r + w δ (r)o(r) δo(δ) + O(δ), whichshows g δ ḡ in C 0 (M), as desired. For (v) we use Lemma 4.5 twice to get R gδ Rḡ = Pḡ(w δ (r)( g ḡ)) + Qḡ(w δ (r)( g ḡ)), 0 = R g + Rḡ + Pḡ( g ḡ) + Qḡ( g ḡ). Multiplying the second line above by w δ (r) and adding it to the first one we get R gδ Rḡ Pḡ(w δ (r)( g ḡ)) w δ (r)pḡ( g ḡ) + Qḡ(w δ (r)( g ḡ)) For convenience put + w δ (r)qḡ( g ḡ) + w δ (r)(rḡ R g ). T 1 = Pḡ(w δ (r)( g ḡ)) w δ (r)pḡ( g ḡ), T 2 = Qḡ(w δ (r)( g ḡ)), T 3 = w δ (r)qḡ( g ḡ), T 4 = w δ (r)(rḡ R g ).
11 Ann Glob Anal Geom (2009) 35: Using Lemmas 4.4 and 4.5 and the fact that jo 1 g = j o 1 ḡ we get: T 1 = Pḡ(w δ (r)( g ḡ)) w δ (r)pḡ( g ḡ) = ḡ(trḡ(w δ (r)( g ḡ))) + w δ (r) ḡ(trḡ( g ḡ)) + i j (w δ (r)( g ij ḡ ij )) w δ (r) i j ( g ij ḡ ij ) w δ (r)( g ḡ), Ricḡ ḡ + w δ (r) g ḡ, Ricḡ ḡ c 1 ( ẅ δ (r) g ḡ + ẇ δ (r) ( g ḡ) ) = ẅ δ (r)r 2 O(r 2 ) = O(δ), r 2 + ẇ δ (r)r O(r) r where c 1 > 0 above is a constant independent of δ. For the second term we get T 2 = Qḡ(w δ (r)( g ḡ)) c(n)( (w δ (r)( g ḡ)) 2 q 3 + (w δ (r)( g ḡ)) (w δ (r)( g ḡ)) 2 q 2 + ( (w δ (r)( g ḡ)) (w δ (r)( g ḡ)) 2 + Ricḡ (w δ (r)( g ḡ)) 2 )q). Notice that there are only first order derivatives in the above estimate. It is easy to see that T 2 = O(δ 2 ).ForT 3 we get T 3 = w δ (r)qḡ( g ḡ) c(n) w δ (r) ( ( g ḡ) 2 q 3 + g ḡ ( g ḡ) 2 q 2 +( g ḡ ( g ḡ) 2 + Ricḡ g ḡ 2 )q) = O(δ 2 ). To estimate T 4 we see that T 4 = w δ (r)(rḡ R g ) =O(δ) since Rḡ(o) = R g (o).thiswayt 1 + T 2 + T 3 + T 4 = O(δ) and (iv) is proved. For (vi) we use Lemma 4.6 (iii). We have that r ( g δ ) ij = 2Ã δ ij,so h gδ = (1/2)Tr gδ (Ã δ ) = (1/2)Tr gδ ( r ( g δ ) ij ). Since g δ ḡ in C 1 (M), r ( g δ ) r ḡ in C 0 (M).Hence,h gδ hḡ in C 0 ( M), as desired. This ends the proof. Theorem A.5 Let M be a compact manifold with boundary, ɛ 0 > 0, o Mandḡametric on M. Put g ḡ M and let Aḡ be the second fundamental form of ḡon M. Then there exists a family of metrics g δ on M such that (i) g δ =ḡinm\ B δ (o), (ii) h gδ = hḡ on B ɛ0 (o, ḡ), (iii) g δ is conformally equivalent to the metric (g 2rAḡ) + dr 2 on B ɛ(δ) (o, ḡ). (iv) g δ ḡinc 1 (M) as δ 0, (v) R gδ Rḡ in C 0 (M) δ 0, (vi) h gδ hḡ in C 0 ( M) as δ 0, Proof Consider Fermi coordinates (x, r) near o. By Lemma 4.6 we get the following expansion of the metric ḡ near o: ḡ(x, r) = (g ij (x) 2rA ij (x) + O(r 2 ))dx i dx j + i O(r 2 )drdx i + dr 2,
12 126 Ann Glob Anal Geom (2009) 35: where ḡ M = g and A ij denotes the second fundamental form of M with respect to ḡ. Consider the metric which has j 1 M ĝ = j 1 M ḡ.nowput where ĝ(x, r) = (g ij (x) 2rA ij (x))dx i dx j + dr 2 g(x, r) = u(x, r) 4/(n 2) ĝ, (11) u(x, t) = r 2 φ 2 (x), φ(x) = n 2 4(n 1) (R ḡ Rĝ). (12) Then u M = u(x, 0) = 0, r u(x, 0) = 0andsoon M, i u = 0, i j u = 0and r u = 0. This way j 1 o g = j 1 o ḡ. The well-known transformation law for the scalar curvature under conformal deformations of the metric gives that ĝu = n 2 4(n 1) (R gu (n+2)/(n 2) Rĝu). In our case u(x, 0) 1 so On the other hand, also on M we have ĝu = α α u ĝu = n 2 4(n 1) (R g Rĝ) on M. (13) =ĝ αβ ( α β u ˆƔ γ αβ γ u) = 2 r u + gij i j u ˆƔ 0 00 r u ˆƔ i 00 i u g ij ( ˆƔ 0 ij r u + ˆƔ k ij ku) = 2 r u. From this last line and Eq. 13 we get that, on M, n 2 4(n 1) (R g Rĝ) = ĝu = r 2 n 2 u = φ(x) = 4(n 1) (R ḡ Rĝ). This way R g = Rḡ on M. Now apply Proposition A.4 to ḡ, g to get a family g δ that satisfies (i) (vi). Theorem A.6 Let M be a compact manifold with boundary, o Mandɛ 0 > 0. Letḡ be a metric on M with hḡ = 0 on B ɛ0 (o). Write g ḡ M,andputAḡ to be the second fundamental form of M.Thenthereexistsafamilyofmetrics g δ such that for δ small enough (compared to ɛ 0 ) the following holds: (i) g δ ḡonm\ B δ (o), (ii) g δ is conformally equivalent to the metric g + dr 2 on B ɛ(δ) (o, ḡ), (iii) g δ ḡinc 0 (M) as δ 0, (iv) R gδ Rḡ in C 0 (M) δ 0, (v) h gδ hḡ in C 0 ( M) as δ 0. Proof The proof of this theorem is similar to Akutagawa and Botvinnik s Approximation Trick (Theorem 4.6 of [1]).
13 Ann Glob Anal Geom (2009) 35: From Eqs. 11 and 12 from the previous proof we may assume that ḡ = in Fermi coordinates near the point o.let ( ) 4 2 r 2 n 2 ( φ(x) (g(x) 2rAḡ(x)) + dr 2) G δ (x, r) = (g(x) 2r(1 w δ (r))aḡ(x)) + dr 2, and put g δ (x, r) = ( ) 4 2 r 2 n 2 φ δ (x, r) Gδ (x, r), φ δ (x, r) = φ(x) 3(n 2) 4(n 1) (2 w δ(r))w δ (r) Aḡ 2 g. We see that (i) and (ii) come from the construction. For (iii) notice that φ δ φ in C 0 (M) and G δ ḡ in C 0 (M), andso g δ ḡ. For (iv) a computation shows that near o we have Since hḡ = 0 on B ɛ0 (o) we get near o.thisway R gδ = R Gδ = R g + 3(1 w δ (r)) 2 Aḡ 2 g (1 w δ(r)) 2 h 2 ḡ (4ẇ δ (r) + 2rẅ δ (r))hḡ + O(δ). R Gδ = R g + 3(1 w δ (r)) 2 Aḡ 2 g + O(δ) ( ) n+2 ( 2 r 2 n 2 φ δ (x, r) +R Gδ (1 + 1 ) 2 r 2 φ δ (x, r)) ( 4(n 2) n 1 G δ ) 2 r 2 φ δ (x, r) ( ) = (1 + O(δ 2 4(n 2) )) n 1 φ + 3(2 w δ(r))w δ (r) Aḡ 2 g + R G δ + O(δ) = R g + 3(1 w δ (r)) 2 Aḡ 2 g + R ḡ R g 3 Aḡ 2 g + 3(2 wδ(r))w δ(r) Aḡ 2 g +O(δ) = Rḡ + O(δ), so (iv) follows. To prove (v) note that near o ( r 2 φ δ ) (x, 0) = 1, r ( r 2 φ δ ) (x, 0) = 0. The usual transformation law for the mean curvature under conformal deformations gives that r u = n 2 2 (h g δ u n/(n 2) h Gδ u). This way, h gδ = h Gδ near o. Sinceh Gδ = hḡ = 0 near o the result follows. Lemma A.7 Let (M, ḡ) be a manifold with boundary and o M such that, in Fermi coordinates (r, x), ḡ = g(x) + dr 2 near o, and so that Rḡ(o) = n(n 1). Lete S+ n be an
14 128 Ann Glob Anal Geom (2009) 35: equatorial point in the boundary of (S n +, g n),sothatinpolarnormalcoordinatesarounde, the round metric g n = dt 2 + sin 2 (t)g n 1.Here,g n 1 denotes the round metric on S n 1. Define g = dt 2 + sin 2 (t)g n 1 (y) around o M, where (t, y) are polar normal coordinates centered at o. Then: (i) Rḡ(o) = R g (o), (ii) j 1 o (ḡ) = j 1 o ( g). Proof Part (i) is direct since R g (o) = R gn (e) = n(n 1).For(ii)wenotethatallfirstorder partial derivatives of ḡ vanish at o since the boundary M has zero second fundamental form near o (see Lemma 4.6 about Fermi coordinates). The same thing holds at e, since the equator in S n is totally geodesic. Lemma A.8 Let (M, ḡ) be a manifold with Y λ (M, ḡ) >0, p 1, p 2 Mandδ > 0. Then there exist a metric g onmand0 < ɛ < δ such that (i) Y (M, [ḡ]) Y (M, [ g]) < δ, (ii) g Bɛ (p i ) around p i is isometric to a neighborhood of e S+ n inside Sn +,fori= 1, 2. (iii) R g 0 on M, (iv) h g = 0 outside a small neighborhood of p i. Proof We start by finding g.sincetheyamabeconstantof(m, ḡ) is positive we may assume that ḡ has positive scalar curvature and minimal boundary. Using Theorem A.6 we can approximate ḡ by a metric ĝ that is conformal to a product near each p i.lemmaa.7 together with Proposition A.4 imply that there exists a metric ǧ on M that is close to ĝ and satisfies (ii). Apply Proposition A.4 to ḡ and ǧ to produce a metric g that coincides with ǧ near p i and with equals ḡ elsewhere. Now g is close to the original ḡ so (i) follows. (ii) holds by construction. Since R g is close to Rḡ > 0, it is non-negative, so (iii) holds. (iv) holds since all constructions took place in a small neighborhood of p i and ḡ had minimal boundary. Let (S+ n, g n), n 3 be the Euclidean unit hemisphere and r the intrinsic distance relative to g n from a point e on the boundary, so that g n = dr 2 + sin 2 rg n 1,whereg n 1 is the standard metric on the unit n 1 hemisphere. For an interval I [0, π] denoted by A(I ) the region A(I ) ={x S+ n : r(x) I }. Lemma A.9 For any ɛ 1 > 0, 0 < ɛ 2 < π there exists a positive function f = f (r) on S n + such that: (i) R g n(n 1) < ɛ 1, where g = f 2 g n, (ii) h g = 0, (iii) Vol(S+ n, g ) 2Vol(S+ n, g n) < ɛ 1, (iv) Area( S+ n, g ) 2Area( S+ n, g n 1) < ɛ 1, (v) f (r) = 1 for r > ɛ 2 and (A([0, ɛ 2 )), g ) is isometric to (A((ɛ 2, π]), g ) = (A((ɛ 2, π]), g n ) for some ɛ 2 < ɛ 2, (vi) 0 < f (r) 1 and f (r) 2/ sin(r) for all r, where means d/dr. Proof This is similar to Lemma 3.1 of [8]. For (ii) note that h gn = 0, g = ( f (1 n)/2 ) 4/(n 1) g 0, so the transformation law for the mean curvature gives h g = 2 n 2 f n(n 1)/2(n 2) η f (1 n)/2.
15 Ann Glob Anal Geom (2009) 35: Since f is a function that depends only on r, the normal derivative η f (1 n)/2 = 0 by Gauss Lemma. This way h g = 0 as desired. The scalar curvature of g is given by 1 n(n 1) R g = 2 n f ( f + (n 1) f cot r) f 2 + f 2. We make the following change of variables: Put Then g = u 2 (dt 2 + g n ) and where = d/dt = (sin r)d/dr.weput so that from (16) weget We fix t 0 > max{0, log cot(ɛ 2 /2)}, andset cos r = tanh t, 0 < r < π, > t >. (14) u(t) = f (r(t)) cosh t. (15) 1 n(n 1) R g = 2 n uu (u ) 2 + n 2 u 2, (16) n B(t) = u n ((u ) 2 u 2 + 1), (17) B (t) = (u n ) (1 R g ). (18) n(n 1) u(t) = cosh t for t (, t 0 ], (19) hence, B(t) 0fort < t 0. We want to consider the solution u of (17) withasuitableb(t). First note that u(t) cosh t for t t 0, if B(t) 0 for t t 0, (20) which follows from a comparison argument. Let B(t) = 0 for t t 0 B(t) 0, 2δ B (t) 0 for t 0 t t B(t) = δ for t t t 1. If δ is sufficiently small, then (17)togetherwith(19)issolvableforu in the interval (, t 1 ) with arbitrary t 1 t 0 + 1, and u (t) >0, u (t) >0fort 0 t t Therefore, taking δ > 0 smaller we have from (18) R g n(n 1) 2(n 1) coshn+1 (t 0 + 1) sinh t 0 δ < ɛ 1, for t t We choose t 1 so that u (t 1 ) = 0andu (t) >0fort < t < t 1.ThiswayR g = n(n 1) for t t t 1.Fort t 1 we put B(t) = B(2t 1 t). Then u(t) = u(2t 1 t) for t t 1. (21) Thus R g n(n 1) < ɛ 1 for all t, and(v) follows from (19) and (21) via (14) and (15). As for the volume we have Vol(S n +, g ) = Vol(S n +, g n) + u(t1 ) 1 du u n u
16 130 Ann Glob Anal Geom (2009) 35: and we can see by a long and elementary calculation that the second term of the right hand side converges to Vol(S+ n, g n) as δ 0. Therefore, (iii) holds for δ small enough, and (iv) follows from an analogous computation. From (20), u(t) cosh t and hence u (t) sinh t from (17), because B(t) 0, which proves (vi). Lemma A.10 Let (M n 1, g 1), (M n 2, g 2), n 3 be two compact Riemannian manifolds with boundary and ɛ > 0. (λ = 1) Ifh gi 0, R gi (p i ) = n(n 1), i = 1, 2 at some points p i M i, then there exists ametricgonm 1 #M 2 so that: (1.a) h g 0 and Vol(M 1 #M 2, g) 2 i=1 Vol(M i, g i ) < ɛ. (1.b) There are isometric embeddings φ i : (M i B i, g i ) (M 1 #M 2, g), i = 1, 2, where B i are small balls around p i M i,and R g (x) n(n 1) < ɛ for x M 1 #M 2 (Im(φ 1 ) Im(φ 2 )). (λ = 1) If R gi 0, R gi (p i ) = n(n 1), h gi > 0 at some points p i M i, i = 1, 2 then there exists a metric g on M 1 #M 2 so that: (0.a) R g 0 and Area( (M 1 #M 2 ), g) 2 i=1 Area( M i, g i ) < ɛ. (0.b) There are isometric embeddings φ i : (M i B i, g i ) (M 1 #M 2, g), i = 1, 2, whereb i are small balls around p i M i,and h g (x) < ɛ for x (M 1 #M 2 ) (Im(φ 1 ) Im(φ 2 ))). Proof Proof of λ = 1. By Lemmas A.4, A.7,andA.9 we can take a metric ḡ i of M i that coincides with g i outside a small (half) ball B i containing p i and such that R gi (x) n(n 1) < ɛ for x B i, Vol(M i, ḡ i ) Vol(M i, g i ) ɛ/4 andb i contains a smaller ball B i such that (B i, ḡ i ) is isometric to a geodesic δ-(half) ball in the unit hemisphere and Vol(B i, ḡ i )<ɛ/4. From Lemma A.9 with ɛ 1, ɛ 2 smaller than ɛ and δ, respectively, we have a small piece (A[δ, δ], g ) for some δ < δ such that R g n(n 1) < ɛ, Vol(A[δ, δ], g )<ɛ/4 and aneighborhoodofeachoftheboundarycomponentsisisometrictoaneighborhoodofthe boundary of the δ-ball inside the hemisphere. This way, the manifold (M 1 #M 2, g) is obtained by putting together (M B i, ḡ 1), (M 2 B 2, ḡ 2) and (A([δ, δ]), g ). The proof of λ = 0issimilar:takeḡ i as above with R gi (x) n(n 1) < ɛ for x B i, Area( M i, ḡ i ) Area( M i, g i ) ɛ/4andb i contains a smaller ball B i such that (B i, ḡ i ) is isometric to a geodesic δ-(half) ball in the unit hemisphere and Area(( M i ) B i, ḡ i ) ɛ/4. From Lemma A.9 with ɛ 1, ɛ 2 smaller than ɛ and δ, respectively, we have a small piece (A[δ, δ], g ) for some δ < δ such that R g n(n 1) < ɛ, Area( A[δ, δ], g )<ɛ/4 and a neighborhood of each of the boundary components is isometric to a neighborhood of the boundary of the δ-ball inside the hemisphere. The manifold (M 1 #M 2, g) is obtained by putting together (M B i, ḡ 1), (M 2 B 2, ḡ 2) and (A([δ, δ]), g ). References 1. Akutagawa, K., Botvinnik, B.: The relative Yamabe invariant. Comm. Anal. Geom. 10(5), (2002) 2. Aubin, T.: Équations différentielles non linéaires et problème de Yamabe concernant la courbure scalaire. J. Math. Pures Appl. 55(3), (1976) 3. Aubin, T.: Some Nonlinear Problems in Riemannian Geometry. Springer-Verlag, Springer Monographs in Mathematics (1998) 4. Brendle, S.: A generalization of the Yamabe flow for manifolds with boundary. Asian J. Math. 6(4), (2002)
17 Ann Glob Anal Geom (2009) 35: Escobar, J.F.: Conformal deformation of a Riemannian metric to a scalar flat metric with constant mean curvature on the boundary. Ann. Math. 136(1), 1 50 (1992) 6. Escobar, J.F.: Conformal deformation of a Riemannian metric to a constant scalar curvature metric with constant mean curvature on the boundary. Indiana Univ. Math. J. 45(4), (1996) 7. Kazdan, J.L., Warner, F.W.: A direct approach to the determination of Gaussian and scalar curvature functions. Invent. Math. 28, (1975) 8. Kobayashi, O.: Scalar curvature of a metric with unit volume. Math. Ann. 279(2), (1987) 9. Marques, F.C.: Conformal deformations to scalar-flat metrics with constant mean curvature on the boundary. Comm. Anal. Geom. 15(2), (2007) 10. Marques, F.C.: Existence results for the Yamabe problem on manifolds with boundary. Indiana Univ. Math. J. 54(6), (2005)
A compactness theorem for Yamabe metrics
A compactness theorem for Yamabe metrics Heather acbeth November 6, 2012 A well-known corollary of Aubin s work on the Yamabe problem [Aub76a] is the fact that, in a conformal class other than the conformal
More informationRigidity and Non-rigidity Results on the Sphere
Rigidity and Non-rigidity Results on the Sphere Fengbo Hang Xiaodong Wang Department of Mathematics Michigan State University Oct., 00 1 Introduction It is a simple consequence of the maximum principle
More informationStability for the Yamabe equation on non-compact manifolds
Stability for the Yamabe equation on non-compact manifolds Jimmy Petean CIMAT Guanajuato, México Tokyo University of Science November, 2015 Yamabe equation: Introduction M closed smooth manifold g =, x
More informationSpectral applications of metric surgeries
Spectral applications of metric surgeries Pierre Jammes Neuchâtel, june 2013 Introduction and motivations Examples of applications of metric surgeries Let (M n, g) be a closed riemannian manifold, and
More informationODE solutions for the fractional Laplacian equations arising in co
ODE solutions for the fractional Laplacian equations arising in conformal geometry Granada, November 7th, 2014 Background Classical Yamabe problem (M n, g) = Riemannian manifold; n 3, g = u 4 n 2 g conformal
More informationInequalities for the ADM-mass and capacity of asymptotically flat manifolds with minimal boundary
Inequalities for the ADM-mass and capacity of asymptotically flat manifolds with minimal boundary Fernando Schwartz Abstract. We present some recent developments involving inequalities for the ADM-mass
More informationClassification of prime 3-manifolds with σ-invariant greater than RP 3
Annals of Mathematics, 159 (2004), 407 424 Classification of prime 3-manifolds with σ-invariant greater than RP 3 By Hubert L. Bray and André Neves* Abstract In this paper we compute the σ-invariants (sometimes
More informationThe Yamabe invariant and surgery
The Yamabe invariant and surgery B. Ammann 1 M. Dahl 2 E. Humbert 3 1 Universität Regensburg Germany 2 Kungliga Tekniska Högskolan, Stockholm Sweden 3 Université François-Rabelais, Tours France Geometric
More informationarxiv: v2 [math.dg] 25 Oct 2014
GAP PHENOMENA AND CURVATURE ESTIMATES FOR CONFORMALLY COMPACT EINSTEIN MANIFOLDS GANG LI, JIE QING AND YUGUANG SHI arxiv:1410.6402v2 [math.dg] 25 Oct 2014 Abstract. In this paper we first use the result
More informationA surgery formula for the (smooth) Yamabe invariant
A surgery formula for the (smooth) Yamabe invariant B. Ammann 1 M. Dahl 2 E. Humbert 3 1 Universität Regensburg Germany 2 Kungliga Tekniska Högskolan, Stockholm Sweden 3 Université Henri Poincaré, Nancy
More informationPart IB GEOMETRY (Lent 2016): Example Sheet 1
Part IB GEOMETRY (Lent 2016): Example Sheet 1 (a.g.kovalev@dpmms.cam.ac.uk) 1. Suppose that H is a hyperplane in Euclidean n-space R n defined by u x = c for some unit vector u and constant c. The reflection
More informationON FRACTAL DIMENSION OF INVARIANT SETS
ON FRACTAL DIMENSION OF INVARIANT SETS R. MIRZAIE We give an upper bound for the box dimension of an invariant set of a differentiable function f : U M. Here U is an open subset of a Riemannian manifold
More informationUNIQUENESS RESULTS ON SURFACES WITH BOUNDARY
UNIQUENESS RESULTS ON SURFACES WITH BOUNDARY XIAODONG WANG. Introduction The following theorem is proved by Bidaut-Veron and Veron [BVV]. Theorem. Let (M n, g) be a compact Riemannian manifold and u C
More informationA surgery formula for the (smooth) Yamabe invariant
A surgery formula for the (smooth) Yamabe invariant B. Ammann 1 M. Dahl 2 E. Humbert 3 1 Universität Regensburg Germany 2 Kungliga Tekniska Högskolan, Stockholm Sweden 3 Université Henri Poincaré, Nancy
More informationMass transportation methods in functional inequalities and a new family of sharp constrained Sobolev inequalities
Mass transportation methods in functional inequalities and a new family of sharp constrained Sobolev inequalities Robin Neumayer Abstract In recent decades, developments in the theory of mass transportation
More informationA surgery formula for the smooth Yamabe invariant
A surgery formula for the smooth Yamabe invariant B. Ammann 1 M. Dahl 2 E. Humbert 3 1 Universität Regensburg Germany 2 Kungliga Tekniska Högskolan, Stockholm Sweden 3 Université Henri Poincaré, Nancy
More informationA surgery formula for the smooth Yamabe invariant
A surgery formula for the smooth Yamabe invariant B. Ammann 1 M. Dahl 2 E. Humbert 3 1 Universität Regensburg Germany 2 Kungliga Tekniska Högskolan, Stockholm Sweden 3 Université Henri Poincaré, Nancy
More informationTHE DOUBLE COVER RELATIVE TO A CONVEX DOMAIN AND THE RELATIVE ISOPERIMETRIC INEQUALITY
J. Aust. Math. Soc. 80 (2006), 375 382 THE DOUBLE COVER RELATIVE TO A CONVEX DOMAIN AND THE RELATIVE ISOPERIMETRIC INEQUALITY JAIGYOUNG CHOE (Received 18 March 2004; revised 16 February 2005) Communicated
More informationRiemannian Curvature Functionals: Lecture I
Riemannian Curvature Functionals: Lecture I Jeff Viaclovsky Park City athematics Institute July 16, 2013 Overview of lectures The goal of these lectures is to gain an understanding of critical points of
More informationEta Invariant and Conformal Cobordism
Annals of Global Analysis and Geometry 27: 333 340 (2005) C 2005 Springer. 333 Eta Invariant and Conformal Cobordism XIANZHE DAI Department of Mathematics, University of California, Santa Barbara, California
More informationON YAMABE CONSTANTS OF RIEMANNIAN PRODUCTS
ON YAMABE CONSTANTS OF RIEMANNIAN PRODUCTS KAZUO AKUTAGAWA, LUIS A. FLORIT, AND JIMMY PETEAN Abstract. For a closed Riemannian manifold M m, g) of constant positive scalar curvature and any other closed
More informationScalar curvature and the Thurston norm
Scalar curvature and the Thurston norm P. B. Kronheimer 1 andt.s.mrowka 2 Harvard University, CAMBRIDGE MA 02138 Massachusetts Institute of Technology, CAMBRIDGE MA 02139 1. Introduction Let Y be a closed,
More informationPart IB Geometry. Theorems. Based on lectures by A. G. Kovalev Notes taken by Dexter Chua. Lent 2016
Part IB Geometry Theorems Based on lectures by A. G. Kovalev Notes taken by Dexter Chua Lent 2016 These notes are not endorsed by the lecturers, and I have modified them (often significantly) after lectures.
More informationA local characterization for constant curvature metrics in 2-dimensional Lorentz manifolds
A local characterization for constant curvature metrics in -dimensional Lorentz manifolds Ivo Terek Couto Alexandre Lymberopoulos August 9, 8 arxiv:65.7573v [math.dg] 4 May 6 Abstract In this paper we
More informationTHREE-MANIFOLDS OF CONSTANT VECTOR CURVATURE ONE
THREE-MANIFOLDS OF CONSTANT VECTOR CURVATURE ONE BENJAMIN SCHMIDT AND JON WOLFSON ABSTRACT. A Riemannian manifold has CVC(ɛ) if its sectional curvatures satisfy sec ε or sec ε pointwise, and if every tangent
More informationYAMABE METRICS AND CONFORMAL TRANSFORMATIONS
Tόhoku Math. J. 44(1992), 251-258 YAMABE METRICS AND CONFORMAL TRANSFORMATIONS OSAMU KOBAYASHI (Received April 11, 1991) Abstract. We derive higher order variational formulas for the Yamabe functional,
More informationDensity of minimal hypersurfaces for generic metrics
Annals of Mathematics 187 (2018), 1 10 Density of minimal hypersurfaces for generic metrics By Kei Irie, Fernando C. Marques, and André Neves Abstract For almost all Riemannian metrics (in the C Baire
More informationThe harmonic map flow
Chapter 2 The harmonic map flow 2.1 Definition of the flow The harmonic map flow was introduced by Eells-Sampson in 1964; their work could be considered the start of the field of geometric flows. The flow
More informationEdge-cone Einstein metrics and Yamabe metrics
joint work with Ilaria Mondello Kazuo AKUTAGAWA (Chuo University) MSJ-SI 2018 The Role of Metrics in the Theory of PDEs at Hokkaido University, July 2018 azuo AKUTAGAWA (Chuo University) (MSJ-SI 2018 at
More informationABSOLUTE CONTINUITY OF FOLIATIONS
ABSOLUTE CONTINUITY OF FOLIATIONS C. PUGH, M. VIANA, A. WILKINSON 1. Introduction In what follows, U is an open neighborhood in a compact Riemannian manifold M, and F is a local foliation of U. By this
More informationBefore you begin read these instructions carefully.
MATHEMATICAL TRIPOS Part IB Thursday, 6 June, 2013 9:00 am to 12:00 pm PAPER 3 Before you begin read these instructions carefully. Each question in Section II carries twice the number of marks of each
More informationDeforming conformal metrics with negative Bakry-Émery Ricci Tensor on manifolds with boundary
Deforming conformal metrics with negative Bakry-Émery Ricci Tensor on manifolds with boundary Weimin Sheng (Joint with Li-Xia Yuan) Zhejiang University IMS, NUS, 8-12 Dec 2014 1 / 50 Outline 1 Prescribing
More informationHandlebody Decomposition of a Manifold
Handlebody Decomposition of a Manifold Mahuya Datta Statistics and Mathematics Unit Indian Statistical Institute, Kolkata mahuya@isical.ac.in January 12, 2012 contents Introduction What is a handlebody
More informationMinimization problems on the Hardy-Sobolev inequality
manuscript No. (will be inserted by the editor) Minimization problems on the Hardy-Sobolev inequality Masato Hashizume Received: date / Accepted: date Abstract We study minimization problems on Hardy-Sobolev
More informationUmbilic cylinders in General Relativity or the very weird path of trapped photons
Umbilic cylinders in General Relativity or the very weird path of trapped photons Carla Cederbaum Universität Tübingen European Women in Mathematics @ Schloss Rauischholzhausen 2015 Carla Cederbaum (Tübingen)
More informationERRATUM TO AFFINE MANIFOLDS, SYZ GEOMETRY AND THE Y VERTEX
ERRATUM TO AFFINE MANIFOLDS, SYZ GEOMETRY AND THE Y VERTEX JOHN LOFTIN, SHING-TUNG YAU, AND ERIC ZASLOW 1. Main result The purpose of this erratum is to correct an error in the proof of the main result
More informationDiscrete groups and the thick thin decomposition
CHAPTER 5 Discrete groups and the thick thin decomposition Suppose we have a complete hyperbolic structure on an orientable 3-manifold. Then the developing map D : M H 3 is a covering map, by theorem 3.19.
More informationMEAN CURVATURE FLOW OF ENTIRE GRAPHS EVOLVING AWAY FROM THE HEAT FLOW
MEAN CURVATURE FLOW OF ENTIRE GRAPHS EVOLVING AWAY FROM THE HEAT FLOW GREGORY DRUGAN AND XUAN HIEN NGUYEN Abstract. We present two initial graphs over the entire R n, n 2 for which the mean curvature flow
More informationCritical metrics on connected sums of Einstein four-manifolds
Critical metrics on connected sums of Einstein four-manifolds University of Wisconsin, Madison March 22, 2013 Kyoto Einstein manifolds Einstein-Hilbert functional in dimension 4: R(g) = V ol(g) 1/2 R g
More informationCalculus of Variations
Calc. Var. DOI 10.1007/s00526-011-0402-2 Calculus of Variations Extension of a theorem of Shi and Tam Michael Eichmair Pengzi Miao Xiaodong Wang Received: 13 November 2009 / Accepted: 31 January 2011 Springer-Verlag
More informationMATH 51H Section 4. October 16, Recall what it means for a function between metric spaces to be continuous:
MATH 51H Section 4 October 16, 2015 1 Continuity Recall what it means for a function between metric spaces to be continuous: Definition. Let (X, d X ), (Y, d Y ) be metric spaces. A function f : X Y is
More informationON THE FOLIATION OF SPACE-TIME BY CONSTANT MEAN CURVATURE HYPERSURFACES
ON THE FOLIATION OF SPACE-TIME BY CONSTANT MEAN CURVATURE HYPERSURFACES CLAUS GERHARDT Abstract. We prove that the mean curvature τ of the slices given by a constant mean curvature foliation can be used
More informationCOMPLETE SPACELIKE HYPERSURFACES IN THE DE SITTER SPACE
Chao, X. Osaka J. Math. 50 (203), 75 723 COMPLETE SPACELIKE HYPERSURFACES IN THE DE SITTER SPACE XIAOLI CHAO (Received August 8, 20, revised December 7, 20) Abstract In this paper, by modifying Cheng Yau
More informationTwo-Step Nilpotent Lie Algebras Attached to Graphs
International Mathematical Forum, 4, 2009, no. 43, 2143-2148 Two-Step Nilpotent Lie Algebras Attached to Graphs Hamid-Reza Fanaï Department of Mathematical Sciences Sharif University of Technology P.O.
More informationA NOTE ON FISCHER-MARSDEN S CONJECTURE
PROCEEDINGS OF THE AMERICAN MATHEMATICAL SOCIETY Volume 125, Number 3, March 1997, Pages 901 905 S 0002-9939(97)03635-6 A NOTE ON FISCHER-MARSDEN S CONJECTURE YING SHEN (Communicated by Peter Li) Abstract.
More informationarxiv: v4 [math.dg] 18 Jun 2015
SMOOTHING 3-DIMENSIONAL POLYHEDRAL SPACES NINA LEBEDEVA, VLADIMIR MATVEEV, ANTON PETRUNIN, AND VSEVOLOD SHEVCHISHIN arxiv:1411.0307v4 [math.dg] 18 Jun 2015 Abstract. We show that 3-dimensional polyhedral
More informationNote on the Chen-Lin Result with the Li-Zhang Method
J. Math. Sci. Univ. Tokyo 18 (2011), 429 439. Note on the Chen-Lin Result with the Li-Zhang Method By Samy Skander Bahoura Abstract. We give a new proof of the Chen-Lin result with the method of moving
More informationMath The Laplacian. 1 Green s Identities, Fundamental Solution
Math. 209 The Laplacian Green s Identities, Fundamental Solution Let be a bounded open set in R n, n 2, with smooth boundary. The fact that the boundary is smooth means that at each point x the external
More informationOn the Intrinsic Differentiability Theorem of Gromov-Schoen
On the Intrinsic Differentiability Theorem of Gromov-Schoen Georgios Daskalopoulos Brown University daskal@math.brown.edu Chikako Mese 2 Johns Hopkins University cmese@math.jhu.edu Abstract In this note,
More informationM. Ledoux Université de Toulouse, France
ON MANIFOLDS WITH NON-NEGATIVE RICCI CURVATURE AND SOBOLEV INEQUALITIES M. Ledoux Université de Toulouse, France Abstract. Let M be a complete n-dimensional Riemanian manifold with non-negative Ricci curvature
More informationLocal semiconvexity of Kantorovich potentials on non-compact manifolds
Local semiconvexity of Kantorovich potentials on non-compact manifolds Alessio Figalli, Nicola Gigli Abstract We prove that any Kantorovich potential for the cost function c = d / on a Riemannian manifold
More informationRIGIDITY OF STATIONARY BLACK HOLES WITH SMALL ANGULAR MOMENTUM ON THE HORIZON
RIGIDITY OF STATIONARY BLACK HOLES WITH SMALL ANGULAR MOMENTUM ON THE HORIZON S. ALEXAKIS, A. D. IONESCU, AND S. KLAINERMAN Abstract. We prove a black hole rigidity result for slowly rotating stationary
More informationDeformation and gluing constructions for scalar curvature, with applications
Deformation and gluing constructions for scalar curvature, with applications Justin Corvino Lafayette College Easton, PA, U.S.A. Geometric Analysis in Geometry and Topology 2014 October 28-October 31,
More informationON WEAKLY NONLINEAR BACKWARD PARABOLIC PROBLEM
ON WEAKLY NONLINEAR BACKWARD PARABOLIC PROBLEM OLEG ZUBELEVICH DEPARTMENT OF MATHEMATICS THE BUDGET AND TREASURY ACADEMY OF THE MINISTRY OF FINANCE OF THE RUSSIAN FEDERATION 7, ZLATOUSTINSKY MALIY PER.,
More informationTHE FORM SUM AND THE FRIEDRICHS EXTENSION OF SCHRÖDINGER-TYPE OPERATORS ON RIEMANNIAN MANIFOLDS
THE FORM SUM AND THE FRIEDRICHS EXTENSION OF SCHRÖDINGER-TYPE OPERATORS ON RIEMANNIAN MANIFOLDS OGNJEN MILATOVIC Abstract. We consider H V = M +V, where (M, g) is a Riemannian manifold (not necessarily
More informationTopological properties
CHAPTER 4 Topological properties 1. Connectedness Definitions and examples Basic properties Connected components Connected versus path connected, again 2. Compactness Definition and first examples Topological
More informationRANDOM FIELDS AND GEOMETRY. Robert Adler and Jonathan Taylor
RANDOM FIELDS AND GEOMETRY from the book of the same name by Robert Adler and Jonathan Taylor IE&M, Technion, Israel, Statistics, Stanford, US. ie.technion.ac.il/adler.phtml www-stat.stanford.edu/ jtaylor
More informationLecture 2: Isoperimetric methods for the curve-shortening flow and for the Ricci flow on surfaces
Lecture 2: Isoperimetric methods for the curve-shortening flow and for the Ricci flow on surfaces Ben Andrews Mathematical Sciences Institute, Australian National University Winter School of Geometric
More informationRecent developments in elliptic partial differential equations of Monge Ampère type
Recent developments in elliptic partial differential equations of Monge Ampère type Neil S. Trudinger Abstract. In conjunction with applications to optimal transportation and conformal geometry, there
More informationAn extremal eigenvalue problem for surfaces with boundary
An extremal eigenvalue problem for surfaces with boundary Richard Schoen Stanford University - Conference in Geometric Analysis, UC Irvine - January 15, 2012 - Joint project with Ailana Fraser Plan of
More informationSHARP BOUNDARY TRACE INEQUALITIES. 1. Introduction
SHARP BOUNDARY TRACE INEQUALITIES GILES AUCHMUTY Abstract. This paper describes sharp inequalities for the trace of Sobolev functions on the boundary of a bounded region R N. The inequalities bound (semi-)norms
More informationAnalysis in weighted spaces : preliminary version
Analysis in weighted spaces : preliminary version Frank Pacard To cite this version: Frank Pacard. Analysis in weighted spaces : preliminary version. 3rd cycle. Téhéran (Iran, 2006, pp.75.
More informationTWO DIMENSIONAL MINIMAL GRAPHS OVER UNBOUNDED DOMAINS
TWO DMENSONAL MNMAL GRAPHS OVER UNBOUNDED DOMANS JOEL SPRUCK Abstract. n this paper we will study solution pairs (u, D) of the minimal surface equation defined over an unbounded domain D in R, with u =
More informationON THE GROUND STATE OF QUANTUM LAYERS
ON THE GROUND STATE OF QUANTUM LAYERS ZHIQIN LU 1. Introduction The problem is from mesoscopic physics: let p : R 3 be an embedded surface in R 3, we assume that (1) is orientable, complete, but non-compact;
More informationA TWO PARAMETERS AMBROSETTI PRODI PROBLEM*
PORTUGALIAE MATHEMATICA Vol. 53 Fasc. 3 1996 A TWO PARAMETERS AMBROSETTI PRODI PROBLEM* C. De Coster** and P. Habets 1 Introduction The study of the Ambrosetti Prodi problem has started with the paper
More informationComplete Surfaces of Constant Gaussian Curvature in Euclidean Space R 3.
Summary of the Thesis in Mathematics by Valentina Monaco Complete Surfaces of Constant Gaussian Curvature in Euclidean Space R 3. Thesis Supervisor Prof. Massimiliano Pontecorvo 19 May, 2011 SUMMARY The
More informationRecent Progress on the Gromov-Lawson Conjecture
Recent Progress on the Gromov-Lawson Conjecture Jonathan Rosenberg (University of Maryland) in part joint work with Boris Botvinnik (University of Oregon) Stephan Stolz (University of Notre Dame) June
More informationON THE STATIC METRIC EXTENSION PROBLEM
ON THE STATIC METRIC EXTENSION PROBLEM STEFAN CZIMEK Abstract. The subject of this Master thesis under the guidance of M. Eichmair is the following theorem of J. Corvino and R. Schoen [5]: Minimal mass
More informationThe Lusin Theorem and Horizontal Graphs in the Heisenberg Group
Analysis and Geometry in Metric Spaces Research Article DOI: 10.2478/agms-2013-0008 AGMS 2013 295-301 The Lusin Theorem and Horizontal Graphs in the Heisenberg Group Abstract In this paper we prove that
More informationLiouville Properties for Nonsymmetric Diffusion Operators. Nelson Castañeda. Central Connecticut State University
Liouville Properties for Nonsymmetric Diffusion Operators Nelson Castañeda Central Connecticut State University VII Americas School in Differential Equations and Nonlinear Analysis We consider nonsymmetric
More informationHomogenization and error estimates of free boundary velocities in periodic media
Homogenization and error estimates of free boundary velocities in periodic media Inwon C. Kim October 7, 2011 Abstract In this note I describe a recent result ([14]-[15]) on homogenization and error estimates
More informationGeometry of Ricci Solitons
Geometry of Ricci Solitons H.-D. Cao, Lehigh University LMU, Munich November 25, 2008 1 Ricci Solitons A complete Riemannian (M n, g ij ) is a Ricci soliton if there exists a smooth function f on M such
More informationFORMATION OF TRAPPED SURFACES II. 1. Introduction
FORMATION OF TRAPPED SURFACES II SERGIU KLAINERMAN, JONATHAN LUK, AND IGOR RODNIANSKI 1. Introduction. Geometry of a null hypersurface As in [?] we consider a region D = D(u, u ) of a vacuum spacetime
More informationδ-hyperbolic SPACES SIDDHARTHA GADGIL
δ-hyperbolic SPACES SIDDHARTHA GADGIL Abstract. These are notes for the Chennai TMGT conference on δ-hyperbolic spaces corresponding to chapter III.H in the book of Bridson and Haefliger. When viewed from
More informationSpectral Gap and Concentration for Some Spherically Symmetric Probability Measures
Spectral Gap and Concentration for Some Spherically Symmetric Probability Measures S.G. Bobkov School of Mathematics, University of Minnesota, 127 Vincent Hall, 26 Church St. S.E., Minneapolis, MN 55455,
More informationOn Shalom Tao s Non-Quantitative Proof of Gromov s Polynomial Growth Theorem
On Shalom Tao s Non-Quantitative Proof of Gromov s Polynomial Growth Theorem Carlos A. De la Cruz Mengual Geometric Group Theory Seminar, HS 2013, ETH Zürich 13.11.2013 1 Towards the statement of Gromov
More informationNon-radial solutions to a bi-harmonic equation with negative exponent
Non-radial solutions to a bi-harmonic equation with negative exponent Ali Hyder Department of Mathematics, University of British Columbia, Vancouver BC V6TZ2, Canada ali.hyder@math.ubc.ca Juncheng Wei
More informationOn Moving Ginzburg-Landau Vortices
communications in analysis and geometry Volume, Number 5, 85-99, 004 On Moving Ginzburg-Landau Vortices Changyou Wang In this note, we establish a quantization property for the heat equation of Ginzburg-Landau
More informationCONFORMAL DEFORMATIONS OF THE SMALLEST EIGENVALUE OF THE RICCI TENSOR. 1. introduction
CONFORMAL DEFORMATIONS OF THE SMALLEST EIGENVALUE OF THE RICCI TENSOR PENGFEI GUAN AND GUOFANG WANG Abstract. We consider deformations of metrics in a given conformal class such that the smallest eigenvalue
More informationLECTURE 15: COMPLETENESS AND CONVEXITY
LECTURE 15: COMPLETENESS AND CONVEXITY 1. The Hopf-Rinow Theorem Recall that a Riemannian manifold (M, g) is called geodesically complete if the maximal defining interval of any geodesic is R. On the other
More informationThe Geometrization Theorem
The Geometrization Theorem Matthew D. Brown Wednesday, December 19, 2012 In this paper, we discuss the Geometrization Theorem, formerly Thurston s Geometrization Conjecture, which is essentially the statement
More informationLocalizing solutions of the Einstein equations
Localizing solutions of the Einstein equations Richard Schoen UC, Irvine and Stanford University - General Relativity: A Celebration of the 100th Anniversary, IHP - November 20, 2015 Plan of Lecture The
More informationIntroduction. Hamilton s Ricci flow and its early success
Introduction In this book we compare the linear heat equation on a static manifold with the Ricci flow which is a nonlinear heat equation for a Riemannian metric g(t) on M and with the heat equation on
More informationPositive mass theorem for the Paneitz-Branson operator
Positive mass theorem for the Paneitz-Branson operator Emmanuel Humbert, Simon Raulot To cite this version: Emmanuel Humbert, Simon Raulot. Positive mass theorem for the Paneitz-Branson operator. Calculus
More informationWARPED PRODUCTS PETER PETERSEN
WARPED PRODUCTS PETER PETERSEN. Definitions We shall define as few concepts as possible. A tangent vector always has the local coordinate expansion v dx i (v) and a function the differential df f dxi We
More informationarxiv: v1 [math.fa] 26 Jan 2017
WEAK APPROXIMATION BY BOUNDED SOBOLEV MAPS WITH VALUES INTO COMPLETE MANIFOLDS PIERRE BOUSQUET, AUGUSTO C. PONCE, AND JEAN VAN SCHAFTINGEN arxiv:1701.07627v1 [math.fa] 26 Jan 2017 Abstract. We have recently
More informationOn a weighted total variation minimization problem
On a weighted total variation minimization problem Guillaume Carlier CEREMADE Université Paris Dauphine carlier@ceremade.dauphine.fr Myriam Comte Laboratoire Jacques-Louis Lions, Université Pierre et Marie
More informationChern-Simons gauge theory The Chern-Simons (CS) gauge theory in three dimensions is defined by the action,
Lecture A3 Chern-Simons gauge theory The Chern-Simons (CS) gauge theory in three dimensions is defined by the action, S CS = k tr (AdA+ 3 ) 4π A3, = k ( ǫ µνρ tr A µ ( ν A ρ ρ A ν )+ ) 8π 3 A µ[a ν,a ρ
More informationAPPROXIMATE YANG MILLS HIGGS METRICS ON FLAT HIGGS BUNDLES OVER AN AFFINE MANIFOLD. 1. Introduction
APPROXIMATE YANG MILLS HIGGS METRICS ON FLAT HIGGS BUNDLES OVER AN AFFINE MANIFOLD INDRANIL BISWAS, JOHN LOFTIN, AND MATTHIAS STEMMLER Abstract. Given a flat Higgs vector bundle (E,, ϕ) over a compact
More informationAsymptotic Behavior of Marginally Trapped Tubes
Asymptotic Behavior of Marginally Trapped Tubes Catherine Williams January 29, 2009 Preliminaries general relativity General relativity says that spacetime is described by a Lorentzian 4-manifold (M, g)
More informationON A DISTANCE DEFINED BY THE LENGTH SPECTRUM ON TEICHMÜLLER SPACE
Annales Academiæ Scientiarum Fennicæ Mathematica Volumen 28, 2003, 315 326 ON A DISTANCE DEFINED BY THE LENGTH SPECTRUM ON TEICHMÜLLER SPACE Hiroshige Shiga Tokyo Institute of Technology, Department of
More informationFENGBO HANG AND PAUL C. YANG
Q CURVATURE ON A CLASS OF 3 ANIFOLDS FENGBO HANG AND PAUL C. YANG Abstract. otivated by the strong maximum principle for Paneitz operator in dimension 5 or higher found in [G] and the calculation of the
More informationSpacelike surfaces with positive definite second fundamental form in 3-dimensional Lorentzian manifolds
Spacelike surfaces with positive definite second fundamental form in 3-dimensional Lorentzian manifolds Alfonso Romero Departamento de Geometría y Topología Universidad de Granada 18071-Granada Web: http://www.ugr.es/
More informationOn boundary primitive manifolds and a theorem of Casson Gordon
Topology and its Applications 125 (2002) 571 579 www.elsevier.com/locate/topol On boundary primitive manifolds and a theorem of Casson Gordon Yoav Moriah 1 Department of Mathematics, Technion, Haifa 32000,
More informationHyperbolic Geometry on Geometric Surfaces
Mathematics Seminar, 15 September 2010 Outline Introduction Hyperbolic geometry Abstract surfaces The hemisphere model as a geometric surface The Poincaré disk model as a geometric surface Conclusion Introduction
More informationDedicated to Professor Linda Rothchild on the occasion of her 60th birthday
REARKS ON THE HOOGENEOUS COPLEX ONGE-APÈRE EQUATION PENGFEI GUAN Dedicated to Professor Linda Rothchild on the occasion of her 60th birthday This short note concerns the homogeneous complex onge-ampère
More informationDIFFERENTIAL GEOMETRY, LECTURE 16-17, JULY 14-17
DIFFERENTIAL GEOMETRY, LECTURE 16-17, JULY 14-17 6. Geodesics A parametrized line γ : [a, b] R n in R n is straight (and the parametrization is uniform) if the vector γ (t) does not depend on t. Thus,
More informationarxiv: v3 [math.dg] 13 Mar 2011
GENERALIZED QUASI EINSTEIN MANIFOLDS WITH HARMONIC WEYL TENSOR GIOVANNI CATINO arxiv:02.5405v3 [math.dg] 3 Mar 20 Abstract. In this paper we introduce the notion of generalized quasi Einstein manifold,
More informationOLIVIA MILOJ March 27, 2006 ON THE PENROSE INEQUALITY
OLIVIA MILOJ March 27, 2006 ON THE PENROSE INEQUALITY Abstract Penrose presented back in 1973 an argument that any part of the spacetime which contains black holes with event horizons of area A has total
More information