McKay Correspondence
|
|
- George Tyler
- 5 years ago
- Views:
Transcription
1 1 McKay Correspondence To the memory of Peter Slodowy Iku Nakamura 005 November
2 1 Dynkin diagrams and ADE The following appear in connection with Dynkin (0) Dynkin diagram ADE (1) Finite subgroups of SL(, C), Regular polyhedra () -dim simple sing (deform-stable critical points) (3) simple Lie algebras ADE, II 1 -factors etc. (4) Partition func. of SL(, Z)-inv. conformal field thrys (5) Finite simple groups Fischer F 4, Baby monster B, Monster M, and McKay s 3rd observation on them (E 6, E 7, E 8 correspond to them)
3 3 A n D n E E E
4 4 Partition funct. of SL(, Z)-inv. conformal field theorys Dofinition: Z =Trq L 0+ L 0 where q = e π 1τ Assumptions 1. Unique vacuum( 1 state of min. energy). χ k : a A (1) 1 -character corresp. to a particle (or an operator in a physical theory) 3. Partition func. Z is a sum of χχ, (χ, χ :A (1) 1 -characters) 4. Z is SL(, Z)-inv., invariant under τ τ 1 (the parameter τ H : upper half-plane)
5 5 Classification of Z Cappelli, Itzykson-Zuber, A.Kato Type k + Partition function Z(q, θ, q, θ) A n n +1 n λ=1 χ λ D r 4r r 1 λ=1 χ λ 1 + χ 4r+1 λ + χ r 1, D r+1 4r r λ=1 χ λ 1 + r 1 λ=1 (χ λ χ 4r λ + χ λ χ 4r λ )+ χ r E 6 1 χ 1 + χ 7 + χ 4 + χ 8 + χ 5 + χ 11 E 7 18 χ 1 + χ 17 + χ 5 + χ 13 + χ 7 + χ 11 + χ 9 +(χ 3 + χ 15 ) χ 9 + χ 9 ( χ 3 + χ 15 ) E 8 30 χ 1 + χ 11 + χ 19 + χ 9 + χ 7 + χ 13 + χ 17 + χ 3
6 6 Indices of χ = Coxeter exponents of ADE Type Partition function Z and Coxeter exponents E 6 χ 1 + χ 7 + χ 4 + χ 8 + χ 5 + χ 11 1, 4, 5, 7, 8, 11 E 7 χ 1 + χ 17 + χ 5 + χ 13 + χ 7 + χ 11 + χ 9 +(χ 3 + χ 15 ) χ 9 + χ 9 ( χ 3 + χ 15 ) 1, 5, 7, 9, 11, 13, 17 E 8 χ 1 + χ 11 + χ 19 + χ 9 + χ 7 + χ 13 + χ 17 + χ 3 1, 7, 11, 13, 17, 19, 3, 9
7 7 (5) McKay s 3rd observation only conj. classes of involutions of Monster M. (Fischer) is one of the classes (Fischer involution). 1. {the conj. class of a b; a, b (Fischer)} = 9 classes. {order of a b; a, b (Fischer)} = {1,,, 3, 3, 4, 4, 5, 6}, the same as mult. of vertices of Ẽ8, extended E 8. 6 Ẽ
8 8 Today McKay correspondence (1) = (0) [Ito-N. 1999] explains McKay (1) = (0) + () by Hilbert scheme of G-orbits G-Hilb(C ) G SL() Recall: (0) Dynkin diagrams ADE (1) Finite subgroups of SL(, C) () -dim. Simple sing. and their resol. (3) Simple Lie algebras ADE
9 9 well known and trivial 1. From finite groups to singularities : (1) = (). From singularities to Dynkin diag. () = (0) Recall: (0) Dynkin diagrams ADE (1) Finite subgroups of SL(, C) () -dim. Simple sing. and their resol. (3) Simple Lie algebras ADE
10 10 well known, but nontrivial 1. From Lie algebra to singulalities (3) = () Grothendieck, Brieskorn, Slodowy. From finite groups to Dynkin (1) = (0) (McKay) 3. Explanation for McKay (1) + () = (0) + () by vector bundles and their Chern classes (Gonzalez-Sprinberg, Verdier) Today [Ito-N. 1999] explains McKay (1) = (0) + () by Hilbert scheme of G-orbits : G-Hilb(C ), G SL()
11 11 More recent progress Topic(4) : Kawahigashi and other (Ann. Math. ) Topic(5) : Conway, Miyamoto, Lam-Yamada-Yamauchi Hot news John McKay received 003 CRM-Feilds-PIMS prize. Reason : Discovery of McKay corresp. and McKay s observation about Monster.
12 1 History Moonshine - Character table of Monster (Fischer-Thompson) McKay correspondence Discovery of (5) - Griess constructs Monster
13 13 3 dim. McKay corresp. thereafter G SL(3) Consider G-Hilb(C 3 ) only. 1. Smoothness G abelian : Nakamura. Smoothness & 3dim McKay corresp. (G abelian : Ito-Nakajima, G general : Bridgeland-King-Reid) 3. Structure G abelian : Nakamura, Craw-Reid 4. Structure of M θ (variants of G-Hilb(C 3 )) G abelian : Craw-Ishii 5. Structure G non-abelian : Gomi-Nakamura-Shinoda
14 14 Today McKay correspondence (1) = (0) [Ito-Nakamura 1999] explain (1) = (0) + () by G-Hilb(C ) : Hilbert scheme of G-orbits G SL() Recall: (0) Dynkin diagrams ADE (1) Finite subgroups of SL(, C) () -dim. Simple sing. and their resol.
15 15 Review : what is McKay correpondence Exam 1 G = G(D 5 ) : a dihedral group of order 1 G : generated by σ and τ σ = ζ ζ6 1, τ =
16 16 Repres Tr(ρ) e e σ σ τ τ 3 ρ 0 χ ρ 1 χ ρ χ ρ 3 χ ρ 4 χ i i ρ 5 χ i i
17 17 Let ρ nat : G SL(, C) (the natural inclusion) Then repres.ρ i and their tensor products with ρ nat ρ ρ nat = ρ 0 + ρ 1 + ρ 3, ρ 0 ρ nat = ρ 1 ρ nat = ρ, ρ 3 ρ nat = ρ + ρ 4 + ρ 5, ρ 4 ρ nat = ρ 3, ρ 5 ρ nat = ρ 3. Draw a graph as follows: D 5 ρ ρ ρ 3 ρ ρ 1 ρ 5 Rule : Connect ρ i and ρ j ρ i ρ nat = ρ j + Remove ρ 0 (triv. repres.).then we get a Dynkin.
18 18 Exam (Continued) G = G(D 5 ) : a dihedral group of order 1 G : generated by σ and τ σ = ζ ζ6 1, τ = The quotient C /G has a unique sing. Invariant polynomials of G(D 5 ) and their relation are F = x 6 + y 6,G = x y,h = xy(x 6 y 6 ) G 4 GF + H =0
19 19 Invariant polynomials of G(D 5 ) and their relation are G 4 GF + H =0 The equation of D 5 is usually refered to as X 4 + XY + Z =0 A unique singularity (F, G, H) =(0, 0, 0) The exceptional set for the sing.(0, 0, 0) C 1 C C 4 C 5 C 3 C 1 C C 3 C 4 6 = C 5 D 5 C i is P 1 (a line), intersecting at most transversely
20 0 The exceptional set for the sing.(0, 0, 0) C 1 C C 4 C 5 C 3 C 1 C C 3 C 4 6 = C 5 D 5 C i is P 1 (a line), intersecting at most transv. The dual grapf of it is a Dynkin diagram D 5 Rule of dual graph : C i = a vertex, C i C j = an edge Conclusion : both Dynkin diagrams are the same (McKay correspondence)
21 1 McKay corresp. asserts : a relationship between (1) and () (1) Resolution of sing. of C /G () Representation theory of G
22 Exam 3 (Continued) G = G(D 5 ) : a dihedral group of order 1 G : generated by σ and τ σ = ζ ζ6 1, τ = The quotient C /G has a unique sing. Invariant polynom. of G(D 5 ) and relation F = x 6 + y 6,G = x y,h = xy(x 6 y 6 ) G 4 GF + H =0
23 3 Invariant polynom. of G(D 5 ) and relation are G 4 GF + H =0 The usual eq. of D 5 : X 4 + XY + Z =0 A unique singularity (F, G, H) =(0, 0, 0) When resolve sing, take quotients H/G = (x6 y 6 ) xy etc. with Denominators/Numerators not G(D 5 )-invariant. But xy, x 6 y 6 belong to the same repres. of G(D 5 ) Therefore Resolution of sing. and Repres. theory of G relate each other.
24 4 3 New resolution of simple sing. We dare to regard C /G as a moduli space C /G ={a G-inv. subset consisting of 1 points} : moduli of geometric G-orbits Resolution of C /G = moduli of ring-theor. G-orbits G - Hilb(C ):={a O C - G - module of length 1} For a module M G - Hilb(C ) 0 I O C M 0 (exact) G-module generating I is almost G-irreducible Example of generators of I : F t = xy t(x 6 y 6 )
25 5 4 The Hilbert scheme of n points The Hilbert scheme of n points in the space X Z : n points of X n points Z is a formal sum Z = n 1 P 1 + n P + + n r P r (P i P j ) (where n = n n r )
26 6 Exam 4 Assume X =C. Let P i : x = α i, I Z = the ideal of Z I Z = f Z C[x] Z is the zero locus f Z (x) Z is n points equiv. dim C C[x]/I Z = n f Z (x) =(x α 1 ) n 1 (x α ) n (x α r ) n r = x n + a 1 x n a n 1 x + a n e.g. if z = n [0], then I Z =(x n ) Hilb n (C) = {n points of X} n 1 bij. = xn + a n j x j ; a j C j=0 = C n
27 7 Exam 5 Assume X =C. Then Z = n 1 P n r P r, (formal sum), P i P j, namely, Z X }{{} n X/order forgotton= X (n) X (n) = X }{{} n X/S n X (n) is very singular, has a lot of sing. Caution X (n) is different from Hilb n (C ).
28 8 Assume X =C. Let X [n] =Hilb n (C ). X [n] = {an ideal I C[x, y]; dim C[x, y]/i = n} I C[x, y]; I : a vector subsp of C[x, y] = xi I,yI I, dim C[x, y]/i = n Thm 1 (Fogarty 1968) X [n] is a resolution of X (n). A natural map π : X [n] X (n) is defined, π : Z n 1 P n r P r where Z = {P 1,,P r },n i = multiplicity of P i in Z.
29 9 Thm (Fogarty 1968)(revisited) The natural morphism X [N] = Hilb N (C ) π X (N) is a resol (mimimal) of sing. The map π sends G-fixed points to G-fixed points. where G SL(), N = G. Then π G-inv. :(X [N] ) G-inv. (X (N) ) G-inv. By Thm of Fogarty (X [N] ) G-inv. is nonsing. G -inv. part of Fogarty = Next theorem
30 30 5 The G-orbit Hilbert scheme of C Lemma 3 (X (N) ) G-inv. =C /G. Def 4 G - Hilb(C ):=(X [N] ) G-inv. G - Hilb(C ) is called the G-orbit Hilbert scheme of C. For I G - Hilb(C ), C[x, y]/i = C[G] regular repres. Thm 5 (Ito-Nakamura 1999) G - Hilb(C ) is a minimal resol. of C /G with enough information about repres. of G.
31 31 Thm 6 (Ito-Nakamura 1999) G - Hilb(C ) is a minimal resol. of C /G with enough information about repres. of G. This gives a new explanation for McKay corresp. Vertices of Dynkin diagram (bijective) Irred. components of except. set (bijective) (McKay corresp.) Eq. class of irred. reps( trivial) of G
32 3 A n... D n... D 5 E 6 E 7 E 8
33 33 A n... D n... D 5 E 6 E 7 E 8
34 34 A n... D n... D 5 E 6 E 7 E 8
35 35 A n... D n... D 5 E 6 E 7 E 8
36 36 A n... D n... D 5 E 6 E 7 E 8
37 37 A n... D n... D 5 E 6 E 7 E 8
38 38 A n... D n... D 5 E 6 E 7 E 8
39 A n... (n vertices) 1 1 D n D 5 E 6 1 E 7 3 E (n vertices)
40 40 6 The exceptional set D 5 case π : G - Hilb(C ) C /G the natural,ap G - Hilb(C ) \ π 1 (0) C /G \{0} (isom.) Let E = π 1 (0) be the exceptional set. Then E = {I G - Hilb(X); I m} where m =(x, y)c[x, y] : the maximal ideal. For I E, we set V (I) =I/(mI + n) where n =(F, G, H)C[x, y]. V (I) isag-module of generators of I other than G-inv. For I G - Hilb(C ), C[x, y]/i =C[G] : Regular rep.
41 41 Define a subset of E by E 1 :={I E; ρ 1 V (I)} = {I G - Hilb; m I,ρ 1 V (I)} E :={I E; V (I) ρ }. We will see E 1 = {I 1 (s); s C} I 1 ( ) P 1, E = {I (s); s C } I (0) I ( ) P 1, I 1 ( ) =I (0) (intersection)
42 4 The exceptional set E, E 1 an irred. comp. of E V (ρ 1 )={xy},v 6 (ρ 1 )={x 6 y 6 } I 1 (s) ={xy + s(x 6 y 6 )} + n I 1 (s) is an ideal generated by xy + s(x 6 y 6 ) and n =(F, G, H). We see, dim C[x, y]/i 1 (s) =1, I 1 (s) G - Hilb(C ) ( s C)
43 43 As s, If E I, we have I n =(F, G, H). Hence C[x, y]/n C[x, y]/i (surjective) E Grass.(C[x, y]/n, codim 11 Grass is compact, so that the sequence I 1 (s) (s C) converges. Now we define: I 1 ( )/n = lim s I 1(s)/n To compute I 1 ( ) = McKay corresp. appears!
44 44 I 1 (s) ={xy + s(x 6 y 6 )} + n (s 0) = { 1 s xy +(x6 y 6 )} + n (s 0) What happens when s =? Let 1 s =0. If I 1 ( ) ={x 6 y 6 } + n, Then I 1 ( ) / X [1], Absurd. The answer : I 1 ( ) ={x 6 y 6 } + {x y, xy } + n Since I 1 (s) n, x y, xy I 1 (s) for s 0. V 3 (ρ )={x y, xy } = {x, y} {xy} = ρ nat V (ρ 1 ) This reminds us of the McKay rule : ρ = ρ nat ρ 1
45 45 Recall E 1 :={I E; ρ 1 V (I)} E :={I E; ρ V (I)}. We saw We will see E 1 = {I 1 (s); s C} I 1 ( ) P 1 E = {I (s); s C} I ( ) P 1
46 46 V 3 (ρ )={x y, xy }, V 5 (ρ 1 )={ y 5,x 5 } Similarly for t 0, we define I (t) :=(x y ty 5,xy + tx 5 )+n We see V (I (t)) ρ. Then, E = {I E; ρ V (I)} P 1 As t 0, by the same reason as I 1 ( ), I (0) (x y, xy )+n
47 47 I (0) = (x y, xy )+(x 6 y 6 )+n = I 1 ( ) Intersection of E 1 and E!! This comes from McKay rule because V 6 (ρ 1 ) = {x 6 y 6 } = {x, y} { y 5,x 5 } mod n = ρ nat V 5 (ρ ) mod n +(x y, xy ) This reminds us of McKay rule : ρ 1 + = ρ nat ρ D 5 ρ 0 ρ ρ 3 ρ 4 ρ ρ 5
48 48 I 1 (s) ={(1/s)(xy) +(x 6 y 6 )+n I 1 ( ) =(x y, xy ) +(x 6 y 6 )+n V 3 (ρ )={x y, xy } = {x, y} {xy} = ρ nat V (ρ 1 ) This reminds us of McKay rule : ρ = ρ nat ρ 1 I (t) =(x y + t( y 5 ),xy + tx 5 )+n I (0) = (x y, xy )+(x 6 y 6 ) + n V 6 (ρ 1 ) {x 6 y 6 } {x, y} { y 5,x 5 } ρ nat V 5 (ρ ) mod n +(x y, xy ) This reminds us of McKay rule : ρ 1 + = ρ nat ρ Let (1/s) =0 t =0,Red part changes into Green.
49 49 E(ρ 1 ) E(ρ ) E(ρ 1 ) I 1 ( ) E(ρ ) I 1 (s) (s C) I (t) (t C ) I (0) V (I 1 (s)) ρ 1, V (I (t)) ρ, V (I 1 ( )) = V (I (0)) ρ 1 ρ s C, t C(s 0) where V (I) =I/(mI + n) generators of I
50 50 D 5 ρ 0 ρ ρ 3 ρ 4 ρ ρ 5 ρ ρ nat = ρ 0 + ρ 1 + ρ 3 ρ 1 ρ nat = ρ How does the Dynkin diag. come out?
51 51 m V m (ρ) Eq. class 1 {x, y} ρ {xy} {x,y } ρ 1 + ρ 3 3 {x y, xy } {x 3 ± iy 3 } ρ + ρ ρ 5 4 {y 4,x 4 } {x 3 y, xy 3 } ρ 3 5 {y 5, x 5 } {xy(x 3 ± ( iy 3 ))} ρ + ρ ρ 5 6 {x 6 y 6 } {x 5 y, xy 5 } ρ 1 + ρ 3 7 {xy 6,x 6 y} ρ Decomposition of the coinv. alg. into repres. of G(D 5 ) Coinv. alg. : C[x, y]/n =C[x, y]/(f, G, H)
52 5 Degree Repr. ρ ρ 1 + ρ 3 ρ + ρ 4 + ρ 5 ρ 3 Degree Repr. ρ ρ 1 + ρ 3 ρ + ρ 4 + ρ 5 The quiver str. of the red part determ. the Dynkin diag. Let V 1 = {x, y} V 1 V (ρ 1 )=V 3 (ρ ), V 1 V 3 (ρ ) V 4 (ρ 3 ), V 1 V 3 (ρ 4 ) V 4 (ρ 3 ),
53 53 Degree Repr. ρ ρ 1 + ρ 3 ρ + ρ 4 + ρ 5 ρ 3 Degree Repr. ρ ρ 1 + ρ 3 ρ + ρ 4 + ρ 5 Quiver str. of Red part determ. Dynkin. Deg.3: V 1 ρ 1 = ρ, where, V 1 = {x, y} Deg.4: V 1 ρ = ρ 3, V 1 ρ 4 = ρ 3, V 1 ρ 5 = ρ 3 Deg.5: V 1 ρ 3 ρ ρ 4 ρ 5 Deg.6: V 1 ρ ρ 1, V 1 ρ 4 0, V 1 ρ 5 0 The green part is contained in I
54 54 Quiver str. of D 5 V (ρ 1 ) V 6 (ρ 1 ) V 3 (ρ ) V 5 (ρ ) V 4 (ρ 3 ) V 3 (ρ 4 ) V 5 (ρ 4 ) V 3 (ρ 5 ) V 5 (ρ 5 )
55 55 Dynkin diagram D 5 V (ρ 1 ) V 6 (ρ 1 ) V 3 (ρ ) V 5 (ρ ) V 4 (ρ 3 ) V 3 (ρ 4 ) V 5 (ρ 4 ) V 3 (ρ 5 ) V 5 (ρ 5 )
56 56 Compute from lower degrees V (ρ 1 ) V 6 (ρ 1 ) V 3 (ρ ) V 5 (ρ ) V 4 (ρ 3 ) V 3 (ρ 4 ) V 5 (ρ 4 ) V 3 (ρ 5 ) V 5 (ρ 5 )
57 57 7 Exceptional set E 6 -case G(E 6 ) SL(, C) (Binary Tetrahedral Group) σ = G(E 6 )= σ, τ, µ order 4 i, 0, τ = 0, 1, µ = 1 0, i 1, 0 where ɛ = e πi/8. ɛ7,ɛ 7, ɛ 5, ɛ G(D 4 ):= σ, τ, normal in G(E 6 ) 1 G(D 4 ) G(E 6 ) Z/3Z 1. C /G(D 4 ) 3:1 C /G(E 6 )
58 58 Irred. rep. of E 6 (irred. character) 1 1 τ µ µ µ 4 µ 5 ( ) ρ ρ ρ ρ 0 ω ω ω ω ρ ω ω ω ω ρ 0 ω ω ω ω ρ ω ω ω ω
59 59 Coinv. alg. of E 6 m V m 1 ρ ρ 3 3 ρ + ρ 4 ρ 1 + ρ 1 + ρ 3 5 ρ + ρ + ρ 6 ρ 3 7 ρ + ρ + ρ 8 ρ 1 + ρ 1 + ρ 3 9 ρ + ρ 10 ρ 3 11 ρ
60 60 V 5 (ρ ) V 7 (ρ ) V 4 (ρ 1 ) V 8 (ρ 1 ) V 5 (ρ ) V 7 (ρ ) V 6 (ρ 3 ) V 5 (ρ ) V 7 (ρ ) V 4 (ρ 1 ) V 8 (ρ 1 ) Dynkin diagram E 6
61 61 V 5 (ρ ) V 7 (ρ ) V 4 (ρ 1 ) V 8 (ρ 1 ) V 5 (ρ ) V 7 (ρ ) V 6 (ρ 3 ) V 5 (ρ ) V 7 (ρ ) V 4 (ρ 1 ) V 8 (ρ 1 ) Dynkin diagram E 6
62 6 A n... D n... D 5 E 6 E 7 E 8
63 63 A n... D n... D 5 E 6 E 7 E 8
64 64 A n... D n... D 5 E 6 E 7 E 8
65 65 A n... D n... D 5 E 6 E 7 E 8
66 66 A n... D n... D 5 E 6 E 7 E 8
67 67 A n... D n... D 5 E 6 E 7 E 8
68 68 A n... D n... D 5 E 6 E 7 E 8
69 69 8 Summary Need only to compute E the exceptional set. Need only to see the coinv. alg. C[x, y]/(f, G, H) G-inv. polyn. are zero in the coinv. alg. Look at coinv. alg. Forget trivial rep. in D, Ẽ. The red part of the coinv. alg. determines Dynkin. Degree Repr. ρ ρ 1 + ρ 3 ρ + ρ 4 + ρ 5 ρ 3 Degree Repr. ρ ρ 1 + ρ 3 ρ + ρ 4 + ρ 5
70 70 For I E : (except. set), we define V (I) :=I/(mI + n) Then V (I) is either irred. or ρ ρ (ρ, ρ irred.) For ρ, ρ irred rep of G, ρ ρ, define subsets of E by E(ρ) :={I E; V (I) ρ} P (ρ, ρ ):={I E; V (I) ρ ρ }
71 71 Thm 7 (Ito-Nakamura 1999) Let G be a finite subgroup of SL(, C). Then (1) G-Hilb(C ) is a min. resol. of C /G. () For any irred rep. ρ of G, ρ trivial, E(ρ) =P 1, The map ρ E(ρ) is McKay corresp. (3) Decomp. rule of ρ nat into irred. rep. determine the quiver str. of the coinv. algebra, from which the intersection P (ρ, ρ ) between E(ρ) come out.
72 7 End Thank you for your attention.
Magda Sebestean. Communicated by P. Pragacz
Serdica Math. J. 30 (2004), 283 292 A SMOOTH FOUR-DIMENSIONAL G-HILBERT SCHEME Magda Sebestean Communicated by P. Pragacz Abstract. When the cyclic group G of order 15 acts with some specific weights on
More informationDu Val Singularities
Du Val Singularities Igor Burban Introduction We consider quotient singularities C 2 /G, where G SL 2 (C) is a finite subgroup. Since we have a finite ring extension C[[x, y]] G C[[x, y]], the Krull dimension
More informationA CHARACTERIZATION OF THE MOONSHINE VERTEX OPERATOR ALGEBRA BY MEANS OF VIRASORO FRAMES. 1. Introduction
A CHARACTERIZATION OF THE MOONSHINE VERTEX OPERATOR ALGEBRA BY MEANS OF VIRASORO FRAMES CHING HUNG LAM AND HIROSHI YAMAUCHI Abstract. In this article, we show that a framed vertex operator algebra V satisfying
More informationChern numbers and Hilbert Modular Varieties
Chern numbers and Hilbert Modular Varieties Dylan Attwell-Duval Department of Mathematics and Statistics McGill University Montreal, Quebec attwellduval@math.mcgill.ca April 9, 2011 A Topological Point
More informationLECTURES ON SYMPLECTIC REFLECTION ALGEBRAS
LECTURES ON SYMPLECTIC REFLECTION ALGEBRAS IVAN LOSEV 16. Symplectic resolutions of µ 1 (0)//G and their deformations 16.1. GIT quotients. We will need to produce a resolution of singularities for C 2n
More informationThe Major Problems in Group Representation Theory
The Major Problems in Group Representation Theory David A. Craven 18th November 2009 In group representation theory, there are many unsolved conjectures, most of which try to understand the involved relationship
More informationSymplectic varieties and Poisson deformations
Symplectic varieties and Poisson deformations Yoshinori Namikawa A symplectic variety X is a normal algebraic variety (defined over C) which admits an everywhere non-degenerate d-closed 2-form ω on the
More informationMacdonald polynomials and Hilbert schemes. Mark Haiman U.C. Berkeley LECTURE
Macdonald polynomials and Hilbert schemes Mark Haiman U.C. Berkeley LECTURE I Introduction to Hall-Littlewood and Macdonald polynomials, and the n! and (n + 1) (n 1) theorems 1 Hall-Littlewood polynomials
More informationGeometry of Conformal Field Theory
Geometry of Conformal Field Theory Yoshitake HASHIMOTO (Tokyo City University) 2010/07/10 (Sat.) AKB Differential Geometry Seminar Based on a joint work with A. Tsuchiya (IPMU) Contents 0. Introduction
More informationOutline. 1 Geometry and Commutative Algebra. 2 Singularities and Resolutions. 3 Noncommutative Algebra and Deformations. 4 Representation Theory
Outline Geometry, noncommutative algebra and representations Iain Gordon http://www.maths.ed.ac.uk/ igordon/ University of Edinburgh 16th December 2006 1 2 3 4 1 Iain Gordon Geometry, noncommutative algebra
More informationON THE EXCEPTIONAL FIBRES OF KLEINIAN SINGULARITIES WILLIAM CRAWLEY-BOEVEY
ON THE EXCEPTIONAL FIBRES OF KLEINIAN SINGULARITIES WILLIAM CRAWLEY-BOEVEY Abstract. We give a new proof, avoiding case-by-case analysis, of a theorem of Y. Ito and I. Nakamura which provides a module-theoretic
More informationALGEBRA QUALIFYING EXAM, FALL 2017: SOLUTIONS
ALGEBRA QUALIFYING EXAM, FALL 2017: SOLUTIONS Your Name: Conventions: all rings and algebras are assumed to be unital. Part I. True or false? If true provide a brief explanation, if false provide a counterexample
More informationAdvanced School and Workshop on Singularities in Geometry and Topology
SMR1671/17 Advanced School and Workshop on Singularities in Geometry and Topology (15 August - 3 September 25) MCKAY correspondence for quotient surface singularities Oswald Riemenschneider Universitat
More informationBinary codes related to the moonshine vertex operator algebra
Binary codes related to the moonshine vertex operator algebra Akihiro Munemasa 1 1 Graduate School of Information Sciences Tohoku University (in collaboration with K. Betsumiya, R. A. L. Betty, M. Harada
More informationMoment map flows and the Hecke correspondence for quivers
and the Hecke correspondence for quivers International Workshop on Geometry and Representation Theory Hong Kong University, 6 November 2013 The Grassmannian and flag varieties Correspondences in Morse
More informationOn the GIT moduli of semistable pairs consisting of a plane cubic curve and a line
On the GIT moduli of semistable pairs consisting of a plane cubic curve and a line Masamichi Kuroda at Tambara Institute of Mathematical Sciences The University of Tokyo August 26, 2015 Masamichi Kuroda
More informationCombinatorics and geometry of E 7
Combinatorics and geometry of E 7 Steven Sam University of California, Berkeley September 19, 2012 1/24 Outline Macdonald representations Vinberg representations Root system Weyl group 7 points in P 2
More informationREPRESENTATION THEORY WEEK 7
REPRESENTATION THEORY WEEK 7 1. Characters of L k and S n A character of an irreducible representation of L k is a polynomial function constant on every conjugacy class. Since the set of diagonalizable
More informationMath 210C. The representation ring
Math 210C. The representation ring 1. Introduction Let G be a nontrivial connected compact Lie group that is semisimple and simply connected (e.g., SU(n) for n 2, Sp(n) for n 1, or Spin(n) for n 3). Let
More information1. Algebraic vector bundles. Affine Varieties
0. Brief overview Cycles and bundles are intrinsic invariants of algebraic varieties Close connections going back to Grothendieck Work with quasi-projective varieties over a field k Affine Varieties 1.
More informationMath 797W Homework 4
Math 797W Homework 4 Paul Hacking December 5, 2016 We work over an algebraically closed field k. (1) Let F be a sheaf of abelian groups on a topological space X, and p X a point. Recall the definition
More informationFrames of the Leech lattice and their applications
Frames of the Leech lattice and their applications Akihiro Munemasa 1 1 Graduate School of Information Sciences Tohoku University August 6, 2009 The Leech lattice A Z-submodule L of rank 24 in R 24 with
More informationHypertoric varieties and hyperplane arrangements
Hypertoric varieties and hyperplane arrangements Kyoto Univ. June 16, 2018 Motivation - Study of the geometry of symplectic variety Symplectic variety (Y 0, ω) Very special but interesting even dim algebraic
More informationmult V f, where the sum ranges over prime divisor V X. We say that two divisors D 1 and D 2 are linearly equivalent, denoted by sending
2. The canonical divisor In this section we will introduce one of the most important invariants in the birational classification of varieties. Definition 2.1. Let X be a normal quasi-projective variety
More informationWe can choose generators of this k-algebra: s i H 0 (X, L r i. H 0 (X, L mr )
MODULI PROBLEMS AND GEOMETRIC INVARIANT THEORY 43 5.3. Linearisations. An abstract projective scheme X does not come with a pre-specified embedding in a projective space. However, an ample line bundle
More informationThe derived category of a GIT quotient
September 28, 2012 Table of contents 1 Geometric invariant theory 2 3 What is geometric invariant theory (GIT)? Let a reductive group G act on a smooth quasiprojective (preferably projective-over-affine)
More informationSPHERICAL UNITARY REPRESENTATIONS FOR REDUCTIVE GROUPS
SPHERICAL UNITARY REPRESENTATIONS FOR REDUCTIVE GROUPS DAN CIUBOTARU 1. Classical motivation: spherical functions 1.1. Spherical harmonics. Let S n 1 R n be the (n 1)-dimensional sphere, C (S n 1 ) the
More informationLECTURE 25-26: CARTAN S THEOREM OF MAXIMAL TORI. 1. Maximal Tori
LECTURE 25-26: CARTAN S THEOREM OF MAXIMAL TORI 1. Maximal Tori By a torus we mean a compact connected abelian Lie group, so a torus is a Lie group that is isomorphic to T n = R n /Z n. Definition 1.1.
More informationH(G(Q p )//G(Z p )) = C c (SL n (Z p )\ SL n (Q p )/ SL n (Z p )).
92 19. Perverse sheaves on the affine Grassmannian 19.1. Spherical Hecke algebra. The Hecke algebra H(G(Q p )//G(Z p )) resp. H(G(F q ((T ))//G(F q [[T ]])) etc. of locally constant compactly supported
More informationExtended groups and representation theory
Extended groups and representation theory Jeffrey Adams David Vogan University of Maryland Massachusetts Institute of Technology CUNY Representation Theory Seminar April 19, 2013 Outline Classification
More information1. Quivers and their representations: Basic definitions and examples.
1 Quivers and their representations: Basic definitions and examples 11 Quivers A quiver Q (sometimes also called a directed graph) consists of vertices and oriented edges (arrows): loops and multiple arrows
More informationHomogeneous Coordinate Ring
Students: Kaiserslautern University Algebraic Group June 14, 2013 Outline Quotients in Algebraic Geometry 1 Quotients in Algebraic Geometry 2 3 4 Outline Quotients in Algebraic Geometry 1 Quotients in
More informationK3 Surfaces and Lattice Theory
K3 Surfaces and Lattice Theory Ichiro Shimada Hiroshima University 2014 Aug Singapore 1 / 26 Example Consider two surfaces S + and S in C 3 defined by w 2 (G(x, y) ± 5 H(x, y)) = 1, where G(x, y) := 9
More informationMath 429/581 (Advanced) Group Theory. Summary of Definitions, Examples, and Theorems by Stefan Gille
Math 429/581 (Advanced) Group Theory Summary of Definitions, Examples, and Theorems by Stefan Gille 1 2 0. Group Operations 0.1. Definition. Let G be a group and X a set. A (left) operation of G on X is
More informationDefinition 9.1. The scheme µ 1 (O)/G is called the Hamiltonian reduction of M with respect to G along O. We will denote by R(M, G, O).
9. Calogero-Moser spaces 9.1. Hamiltonian reduction along an orbit. Let M be an affine algebraic variety and G a reductive algebraic group. Suppose M is Poisson and the action of G preserves the Poisson
More informationCOURSE SUMMARY FOR MATH 504, FALL QUARTER : MODERN ALGEBRA
COURSE SUMMARY FOR MATH 504, FALL QUARTER 2017-8: MODERN ALGEBRA JAROD ALPER Week 1, Sept 27, 29: Introduction to Groups Lecture 1: Introduction to groups. Defined a group and discussed basic properties
More informationSome notes on Coxeter groups
Some notes on Coxeter groups Brooks Roberts November 28, 2017 CONTENTS 1 Contents 1 Sources 2 2 Reflections 3 3 The orthogonal group 7 4 Finite subgroups in two dimensions 9 5 Finite subgroups in three
More informationDerived Canonical Algebras as One-Point Extensions
Contemporary Mathematics Derived Canonical Algebras as One-Point Extensions Michael Barot and Helmut Lenzing Abstract. Canonical algebras have been intensively studied, see for example [12], [3] and [11]
More information12. Hilbert Polynomials and Bézout s Theorem
12. Hilbert Polynomials and Bézout s Theorem 95 12. Hilbert Polynomials and Bézout s Theorem After our study of smooth cubic surfaces in the last chapter, let us now come back to the general theory of
More informationWe then have an analogous theorem. Theorem 1.2.
1. K-Theory of Topological Stacks, Ryan Grady, Notre Dame Throughout, G is sufficiently nice: simple, maybe π 1 is free, or perhaps it s even simply connected. Anyway, there are some assumptions lurking.
More informationCategory O and its basic properties
Category O and its basic properties Daniil Kalinov 1 Definitions Let g denote a semisimple Lie algebra over C with fixed Cartan and Borel subalgebras h b g. Define n = α>0 g α, n = α
More informationThe Hecke category (part II Satake equivalence)
The Hecke category (part II Satake equivalence) Ryan Reich 23 February 2010 In last week s lecture, we discussed the Hecke category Sph of spherical, or (Ô)-equivariant D-modules on the affine grassmannian
More informationGeometric Structure and the Local Langlands Conjecture
Geometric Structure and the Local Langlands Conjecture Paul Baum Penn State Representations of Reductive Groups University of Utah, Salt Lake City July 9, 2013 Paul Baum (Penn State) Geometric Structure
More informationarxiv:alg-geom/ v1 21 Mar 1996
AN INTERSECTION NUMBER FOR THE PUNCTUAL HILBERT SCHEME OF A SURFACE arxiv:alg-geom/960305v 2 Mar 996 GEIR ELLINGSRUD AND STEIN ARILD STRØMME. Introduction Let S be a smooth projective surface over an algebraically
More informationAlgebraic group actions and quotients
23rd Autumn School in Algebraic Geometry Algebraic group actions and quotients Wykno (Poland), September 3-10, 2000 LUNA S SLICE THEOREM AND APPLICATIONS JEAN MARC DRÉZET Contents 1. Introduction 1 2.
More informationLecture 1. Toric Varieties: Basics
Lecture 1. Toric Varieties: Basics Taras Panov Lomonosov Moscow State University Summer School Current Developments in Geometry Novosibirsk, 27 August1 September 2018 Taras Panov (Moscow University) Lecture
More informationModuli spaces of sheaves and the boson-fermion correspondence
Moduli spaces of sheaves and the boson-fermion correspondence Alistair Savage (alistair.savage@uottawa.ca) Department of Mathematics and Statistics University of Ottawa Joint work with Anthony Licata (Stanford/MPI)
More informationORAL QUALIFYING EXAM QUESTIONS. 1. Algebra
ORAL QUALIFYING EXAM QUESTIONS JOHN VOIGHT Below are some questions that I have asked on oral qualifying exams (starting in fall 2015). 1.1. Core questions. 1. Algebra (1) Let R be a noetherian (commutative)
More informationMA 206 notes: introduction to resolution of singularities
MA 206 notes: introduction to resolution of singularities Dan Abramovich Brown University March 4, 2018 Abramovich Introduction to resolution of singularities 1 / 31 Resolution of singularities Let k be
More informationSemistable Representations of Quivers
Semistable Representations of Quivers Ana Bălibanu Let Q be a finite quiver with no oriented cycles, I its set of vertices, k an algebraically closed field, and Mod k Q the category of finite-dimensional
More informationHYPERKÄHLER MANIFOLDS
HYPERKÄHLER MANIFOLDS PAVEL SAFRONOV, TALK AT 2011 TALBOT WORKSHOP 1.1. Basic definitions. 1. Hyperkähler manifolds Definition. A hyperkähler manifold is a C Riemannian manifold together with three covariantly
More informationRepresentation Theory
Representation Theory Representations Let G be a group and V a vector space over a field k. A representation of G on V is a group homomorphism ρ : G Aut(V ). The degree (or dimension) of ρ is just dim
More informationThe Terwilliger algebra of a Q-polynomial distance-regular graph with respect to a set of vertices
The Terwilliger algebra of a Q-polynomial distance-regular graph with respect to a set of vertices Hajime Tanaka (joint work with Rie Tanaka and Yuta Watanabe) Research Center for Pure and Applied Mathematics
More informationMath 249B. Tits systems
Math 249B. Tits systems 1. Introduction Let (G, T ) be a split connected reductive group over a field k, and Φ = Φ(G, T ). Fix a positive system of roots Φ + Φ, and let B be the unique Borel k-subgroup
More informationADE Dynkin diagrams in algebra, geometry and beyond based on work of Ellen Kirkman
ADE Dynkin diagrams in algebra, geometry and beyond based on work of Ellen Kirkman James J. Zhang University of Washington, Seattle, USA at Algebra Extravaganza! Temple University July 24-28, 2017 Happy
More informationToric Varieties. Madeline Brandt. April 26, 2017
Toric Varieties Madeline Brandt April 26, 2017 Last week we saw that we can define normal toric varieties from the data of a fan in a lattice. Today I will review this idea, and also explain how they can
More informationRepresentations and Linear Actions
Representations and Linear Actions Definition 0.1. Let G be an S-group. A representation of G is a morphism of S-groups φ G GL(n, S) for some n. We say φ is faithful if it is a monomorphism (in the category
More informationOn a theorem of Ziv Ran
INSTITUTUL DE MATEMATICA SIMION STOILOW AL ACADEMIEI ROMANE PREPRINT SERIES OF THE INSTITUTE OF MATHEMATICS OF THE ROMANIAN ACADEMY ISSN 0250 3638 On a theorem of Ziv Ran by Cristian Anghel and Nicolae
More informationALGEBRAIC HYPERBOLICITY OF THE VERY GENERAL QUINTIC SURFACE IN P 3
ALGEBRAIC HYPERBOLICITY OF THE VERY GENERAL QUINTIC SURFACE IN P 3 IZZET COSKUN AND ERIC RIEDL Abstract. We prove that a curve of degree dk on a very general surface of degree d 5 in P 3 has geometric
More informationToshiaki Shoji (Nagoya University) Character sheaves on a symmetric space and Kostka polynomials July 27, 2012, Osaka 1 / 1
Character sheaves on a symmetric space and Kostka polynomials Toshiaki Shoji Nagoya University July 27, 2012, Osaka Character sheaves on a symmetric space and Kostka polynomials July 27, 2012, Osaka 1
More informationOLIVIER SERMAN. Theorem 1.1. The moduli space of rank 3 vector bundles over a curve of genus 2 is a local complete intersection.
LOCAL STRUCTURE OF SU C (3) FOR A CURVE OF GENUS 2 OLIVIER SERMAN Abstract. The aim of this note is to give a precise description of the local structure of the moduli space SU C (3) of rank 3 vector bundles
More informationINTRODUCTION TO GEOMETRIC INVARIANT THEORY
INTRODUCTION TO GEOMETRIC INVARIANT THEORY JOSÉ SIMENTAL Abstract. These are the expanded notes for a talk at the MIT/NEU Graduate Student Seminar on Moduli of sheaves on K3 surfaces. We give a brief introduction
More informationLECTURE 11: SOERGEL BIMODULES
LECTURE 11: SOERGEL BIMODULES IVAN LOSEV Introduction In this lecture we continue to study the category O 0 and explain some ideas towards the proof of the Kazhdan-Lusztig conjecture. We start by introducing
More informationCluster varieties for tree-shaped quivers and their cohomology
Cluster varieties for tree-shaped quivers and their cohomology Frédéric Chapoton CNRS & Université de Strasbourg Octobre 2016 Cluster algebras and the associated varieties Cluster algebras are commutative
More informationRoot system chip-firing
Root system chip-firing PhD Thesis Defense Sam Hopkins Massachusetts Institute of Technology April 27th, 2018 Includes joint work with Pavel Galashin, Thomas McConville, Alexander Postnikov, and James
More informationAlgebraic Cobordism. 2nd German-Chinese Conference on Complex Geometry East China Normal University Shanghai-September 11-16, 2006.
Algebraic Cobordism 2nd German-Chinese Conference on Complex Geometry East China Normal University Shanghai-September 11-16, 2006 Marc Levine Outline: Describe the setting of oriented cohomology over a
More informationThe Hilbert-Mumford Criterion
The Hilbert-Mumford Criterion Klaus Pommerening Johannes-Gutenberg-Universität Mainz, Germany January 1987 Last change: April 4, 2017 The notions of stability and related notions apply for actions of algebraic
More informationwhere m is the maximal ideal of O X,p. Note that m/m 2 is a vector space. Suppose that we are given a morphism
8. Smoothness and the Zariski tangent space We want to give an algebraic notion of the tangent space. In differential geometry, tangent vectors are equivalence classes of maps of intervals in R into the
More informationTopic Proposal Applying Representation Stability to Arithmetic Statistics
Topic Proposal Applying Representation Stability to Arithmetic Statistics Nir Gadish Discussed with Benson Farb 1 Introduction The classical Grothendieck-Lefschetz fixed point formula relates the number
More informationPresenting and Extending Hecke Endomorphism Algebras
Presenting and Extending Hecke Endomorphism Algebras Jie Du University of New South Wales Shanghai Conference on Representation Theory 7-11 December 2015 1 / 27 The Hecke Endomorphism Algebra The (equal
More informationMCKAY CORRESPONDENCE. Vadim Schechtman. September 2014
Colloquium talk, Institut de Mathématiques de Toulouse September 2014 Plan Ÿ1. Classical 1.1. Platonic solids. 1.2. Finite subgroups of SU(2). 1.3. Kleinian singularities and graphs A, D, E. 1.4. Root
More informationON THE CLASSIFICATION OF RANK 1 GROUPS OVER NON ARCHIMEDEAN LOCAL FIELDS
ON THE CLASSIFICATION OF RANK 1 GROUPS OVER NON ARCHIMEDEAN LOCAL FIELDS LISA CARBONE Abstract. We outline the classification of K rank 1 groups over non archimedean local fields K up to strict isogeny,
More informationIsogeny invariance of the BSD conjecture
Isogeny invariance of the BSD conjecture Akshay Venkatesh October 30, 2015 1 Examples The BSD conjecture predicts that for an elliptic curve E over Q with E(Q) of rank r 0, where L (r) (1, E) r! = ( p
More informationIntertwining integrals on completely solvable Lie groups
s on s on completely solvable Lie June 16, 2011 In this talk I shall explain a topic which interests me in my collaboration with Ali Baklouti and Jean Ludwig. s on In this talk I shall explain a topic
More informationAN INTRODUCTION TO MODULI SPACES OF CURVES CONTENTS
AN INTRODUCTION TO MODULI SPACES OF CURVES MAARTEN HOEVE ABSTRACT. Notes for a talk in the seminar on modular forms and moduli spaces in Leiden on October 24, 2007. CONTENTS 1. Introduction 1 1.1. References
More informationConditions for the Equivalence of Largeness and Positive vb 1
Conditions for the Equivalence of Largeness and Positive vb 1 Sam Ballas November 27, 2009 Outline 3-Manifold Conjectures Hyperbolic Orbifolds Theorems on Largeness Main Theorem Applications Virtually
More informationMODULI OF ALGEBRAIC SL 3 -VECTOR BUNDLES OVER ADJOINT REPRESENTATION
Masuda, K. Osaka J. Math. 38 (200), 50 506 MODULI OF ALGEBRAIC SL 3 -VECTOR BUNDLES OVER ADJOINT REPRESENTATION KAYO MASUDA (Received June 2, 999). Introduction and result Let be a reductive complex algebraic
More informationE 0 0 F [E] + [F ] = 3. Chern-Weil Theory How can you tell if idempotents over X are similar?
. Characteristic Classes from the viewpoint of Operator Theory. Introduction Overarching Question: How can you tell if two vector bundles over a manifold are isomorphic? Let X be a compact Hausdorff space.
More informationCharacter tables for some small groups
Character tables for some small groups P R Hewitt U of Toledo 12 Feb 07 References: 1. P Neumann, On a lemma which is not Burnside s, Mathematical Scientist 4 (1979), 133-141. 2. JH Conway et al., Atlas
More informationLemma 1.3. The element [X, X] is nonzero.
Math 210C. The remarkable SU(2) Let G be a non-commutative connected compact Lie group, and assume that its rank (i.e., dimension of maximal tori) is 1; equivalently, G is a compact connected Lie group
More informationSince G is a compact Lie group, we can apply Schur orthogonality to see that G χ π (g) 2 dg =
Problem 1 Show that if π is an irreducible representation of a compact lie group G then π is also irreducible. Give an example of a G and π such that π = π, and another for which π π. Is this true for
More informationSimple connectedness of the 3-local geometry of the Monster. A.A. Ivanov. U. Meierfrankenfeld
Simple connectedness of the 3-local geometry of the Monster A.A. Ivanov U. Meierfrankenfeld Abstract We consider the 3-local geometry M of the Monster group M introduced in [BF] as a locally dual polar
More informationOn the geometric Langlands duality
On the geometric Langlands duality Peter Fiebig Emmy Noether Zentrum Universität Erlangen Nürnberg Schwerpunkttagung Bad Honnef April 2010 Outline This lecture will give an overview on the following topics:
More informationMath 121 Homework 4: Notes on Selected Problems
Math 121 Homework 4: Notes on Selected Problems 11.2.9. If W is a subspace of the vector space V stable under the linear transformation (i.e., (W ) W ), show that induces linear transformations W on W
More informationPICARD GROUPS OF MODULI PROBLEMS II
PICARD GROUPS OF MODULI PROBLEMS II DANIEL LI 1. Recap Let s briefly recall what we did last time. I discussed the stack BG m, as classifying line bundles by analyzing the sense in which line bundles may
More informationCohomology theories on projective homogeneous varieties
Cohomology theories on projective homogeneous varieties Baptiste Calmès RAGE conference, Emory, May 2011 Goal: Schubert Calculus for all cohomology theories Schubert Calculus? Cohomology theory? (Very)
More informationof S 2 (Γ(p)). (Hecke, 1928)
Equivariant Atkin-Lehner Theory Introduction Atkin-Lehner Theory: Atkin-Lehner (1970), Miyake (1971), Li (1975): theory of newforms (+ T-algebra action) a canonical basis for S k (Γ 1 (N)) and hence also
More informationLanglands parameters and finite-dimensional representations
Langlands parameters and finite-dimensional representations Department of Mathematics Massachusetts Institute of Technology March 21, 2016 Outline What Langlands can do for you Representations of compact
More informationGEOMETRIC STRUCTURES OF SEMISIMPLE LIE ALGEBRAS
GEOMETRIC STRUCTURES OF SEMISIMPLE LIE ALGEBRAS ANA BALIBANU DISCUSSED WITH PROFESSOR VICTOR GINZBURG 1. Introduction The aim of this paper is to explore the geometry of a Lie algebra g through the action
More informationk=0 /D : S + S /D = K 1 2 (3.5) consistently with the relation (1.75) and the Riemann-Roch-Hirzebruch-Atiyah-Singer index formula
20 VASILY PESTUN 3. Lecture: Grothendieck-Riemann-Roch-Hirzebruch-Atiyah-Singer Index theorems 3.. Index for a holomorphic vector bundle. For a holomorphic vector bundle E over a complex variety of dim
More informationReconstruction algebras of type D (II) Michael Wemyss
Hokkaido Mathematical Journal Vol. 42 (203) p. 293 329 Reconstruction algebras of type D (II) Michael Wemyss (Received July 7, 20; Revised August 9, 202) Abstract. This is the third in a series of papers
More informationInstanton counting, Donaldson invariants, line bundles on moduli spaces of sheaves on rational surfaces. Lothar Göttsche ICTP, Trieste
Instanton counting, Donaldson invariants, line bundles on moduli spaces of sheaves on rational surfaces Lothar Göttsche ICTP, Trieste joint work with Hiraku Nakajima and Kota Yoshioka AMS Summer Institute
More informationBirational geometry and deformations of nilpotent orbits
arxiv:math/0611129v1 [math.ag] 6 Nov 2006 Birational geometry and deformations of nilpotent orbits Yoshinori Namikawa In order to explain what we want to do in this paper, let us begin with an explicit
More informationA REMARK ON THE THEOREM OF OHSAWA-TAKEGOSHI
K. Diederich and E. Mazzilli Nagoya Math. J. Vol. 58 (2000), 85 89 A REMARK ON THE THEOREM OF OHSAWA-TAKEGOSHI KLAS DIEDERICH and EMMANUEL MAZZILLI. Introduction and main result If D C n is a pseudoconvex
More informationTHE GL(2, C) MCKAY CORRESPONDENCE
THE GL(2, C) MCKAY CORRESPONDENCE MICHAEL WEMYSS Abstract. In this paper we show that for any affine complete rational surface singularity the quiver of the reconstruction algebra can be determined combinatorially
More informationHILBERT SCHEMES: GEOMETRY, COMBINATORICS, AND REPRESENTATION THEORY. 1. Introduction
HILBERT SCHEMES: GEOMETRY, COMBINATORICS, AND REPRESENTATION THEORY DORI BEJLERI Abstract. This survey will give an introduction to the theory of Hilbert schemes of points on a surface. These are compactifications
More informationQuantizations and classical non-commutative non-associative algebras
Journal of Generalized Lie Theory and Applications Vol. (008), No., 35 44 Quantizations and classical non-commutative non-associative algebras Hilja Lisa HURU and Valentin LYCHAGIN Department of Mathematics,
More informationVarieties of Characters
Sean Lawton George Mason University Fall Eastern Sectional Meeting September 25, 2016 Lawton (GMU) (AMS, September 2016) Step 1: Groups 1 Let Γ be a finitely generated group. Lawton (GMU) (AMS, September
More informationLocal conformal nets arising from framed vertex operator algebras
Local conformal nets arising from framed vertex operator algebras Yasuyuki Kawahigashi Department of Mathematical Sciences University of Tokyo, Komaba, Tokyo, 153-8914, Japan e-mail: yasuyuki@ms.u-tokyo.ac.jp
More informationCONJECTURES ON CHARACTER DEGREES FOR THE SIMPLE THOMPSON GROUP
Uno, K. Osaka J. Math. 41 (2004), 11 36 CONJECTURES ON CHARACTER DEGREES FOR THE SIMPLE THOMPSON GROUP Dedicated to Professor Yukio Tsushima on his sixtieth birthday KATSUHIRO UNO 1. Introduction (Received
More information