Möbius Inversion Formula and Applications to Cyclotomic Polynomials
|
|
- Anne Randall
- 6 years ago
- Views:
Transcription
1 Degree Project Möbius Inversion Formula and Applications to Cyclotomic Polynomials Author: Zeynep Islek Subject: Mathematics Level: Bachelor Course code: 2MA11E
2 Abstract This report investigates some properties of arithmetic functions. We will prove Möbius inversion formula which is very important in number theory. Also our report investigates roots of unity and cyclotomic polynomials over the complex numbers. 2
3 Contents 1 Introduction 4 2 Arithmetic Functions The Möbius Function The Euler Function Möbius Inversion Formula Cyclotomic Polynomials and Roots of Unity nth Root of Unity Cyclotomic Polynomials Conclusion 23 3
4 1 Introduction The number theory is a very important part of mathematics. We can say that it is a basis of mathematics. Carl Freidrich Gauss who is a very famous mathematician, was said that : Mathematics is the queen of science and arithmetics is the queen of mathematics. The classic Möbius function is an important multiplicative function in the number theory and combinatorics. In number theory there are two very important multiplicative functions which are Möbius function and Euler s function, denoted by µ and ϕ respectively. The Möbius µ introduced to solve a problem which was related to Riemann zeta function. The Euler s function ϕ introduced to generalize a congruence result of Fermat but in this study we are not interested in congruence relating and Riemann zeta function. The classic Möbius function is defined by the August Ferdinant Möbius, in It is a function whose domain is the positive integers, and which is defined as follows: µ(n) = 1 if n = 1 0 if n is divisible by a square bigger than 1 ( 1) k if n is product of k distinct primes Dedekind and Liouville reported the inversion theorem for sums, simultaneously. In 1857 they gave some appliction to ϕ(m). R.Dedekind redeploid the function in the reverse of series which is given by Möbius. E.Laguerre described the function below, using the function which is written by Dedekind. If F (m) = f(d) where d ranges over the divisors of m, then f(m) = µ( m )F (d). (1) d d m When these formulas and (1) were used, this formula was gotten: ϕ(d) = m. F. Mertens noted that if n > 1, µ(d) = 0 where d ranges over the divisors of n. A.F. Möbius recognized its arithmetical importance, in Möbius anaylsed the inverse of f which is an arbitrary function, using the Dirichlet series. Liouville and Dedekind gave the finite form of the Möbius inversion formula, in 1857, as follows g(n) = f(d) f(n) = µ(d)g( n d ). 4
5 If you want to learn more details about history of these functions, please read [1]. Now we will mention relationship between Möbius function and roots of unity, but before we will give some definitions. A polynomial, not identically zero, is said to be irreducible if it cannot be written as a product of two or more non-trivial polynomials whose coefficients are of specified type. If you want to learn more, please check [2, 3, 4]. Every non-zero polynomial over C can be factored as p(x) = α(x z 1 )... (x z n ) where n is the degree, α is the leading coefficient and z 1,..., z n the zeroes of p(x). If α C and rational numbers c 1,..., c n exist satifying α n + c 1 α n c n = 0 then α is called an algebraic numbers. If you want to read more details, please check [3, 5, 6, 7]. Let s take any algebraic number α. The minimal polynomial of α is the unique irreducible polynomial of the smallest degree p(x) with rational coefficients such that p(α) = 0 and whose leading coefficients 1. If you want to learn more details about minimal polynomials, please read [8]. In mathematics, a root of unity, is any complex number that equals 1 when raised to some integer power n. Roots of unity is important in number theory. An nth root of unity, is a complex number z satisfying the equation z n = 1 where n = 1, 2, 3,... is a positive interger. An each element of this sum, which is shown e 2πik n implies that nth root and k for the kth power. Equivalentely, we can use (e 2πi n ) k n instead of e 2πik n, in the complex plane. An nth root of unity is primitive if it is not a kth root of unity for some smaller k: z k 1, k = 1, 2,..., n 1. The zeroes of the polynomial p(z) = z n 1 are the nth roots of unity, each with multiplicity 1. There is a unique monic polynomial Φ n (x) having degree ϕ(n) whose root are the distinct primitive nth roots of unity, where ϕ is an Euler s function. Φ is called a cyclotomic polynomial. Finally, we can say that about this study. In the first part of this thesis, we emphasize the Möbius function and we prove the Möbius inversion formula. Using this Möbius inversion formula, we prove some theorems. In 5
6 the second part we emphasize the roots of unity in the complex numbers, correspondingly we emphasize the cyclotomic polynomials in the complex numbers, and we will see the connection between the Möbius inversion formula and the cyclotomic polynomials in the complex numbers. 6
7 2 Arithmetic Functions In this section we describe Möbius function and Möbius inversion formula, then we prove these functions. Also we prove some theorems which we need for proving Möbius inversion formula. Now we start to give some definition about the number theory. Definition 2.1. A real or complex valued function defined on the positive integers is called an arithmetic function. In set notation: f : Z + R or f : Z + C If you want to see more details on arithmetic functions, check [9]. Definition 2.2. An arithmetic function f is called multiplicative if f(mn) = f(m)f(n) where m and n are relatively prime positive integers (i.e. (m, n) = 1). Definition 2.3. An arithmetic function f is called completely multiplicative if f(mn) = f(m)f(n) for every positive integers m and n. Example 1. The function f(x) = 1 x arithmetic function where f : Z+ R, because since all x in Z +, the results are in R. Let s take x = 2, then f(x) = 1 x = 1 2, and 1 2 is in R. Now it is necessary to learn next definition for continue apprehensibly. Definition 2.4. Let a, b Z and a 0 such that b = ax if there exist x Z, then we say that a divides b which can be denoted a b, and a b if and only if b = ax for all x in Z. 2.1 The Möbius Function The arithmetic function µ(n), defined for all natural numbers, is called Möbius function. Definition 2.5. The Möbius function µ(n) is defined as follows 1 if n = 1 µ(n) = 0 if n is divisible by a square larger than 1 ( 1) k if n = p 1... p k where p i s are relatively prime numbers 7
8 Example 2. We have µ(1) = 1 it is clear to see from the definition. Moreover µ(2) = 1 because 2 is a prime number. So µ(2) = ( 1) 1 = 1. We have µ(4) = 0 because or we can say that 4 is divisible by a square. We have because We have µ(8) = 0 µ(42) = 1 because 42 = 2 3 7, so 42 can be written as the product of three relatively prime numbers. Thus µ(42) = ( 1) 3 = 1. Theorem 2.1. The function µ(n) is multiplicative. Proof. We will prove that µ(mn) = µ(m)µ(n) whenever m and n are relatively prime numbers. First, we consider m and n are square-free numbers. We assume that m = p 1... p k, where p 1,..., p k are distinct primes, and n = q 1... q s, where q 1,..., q s are distinct primes. From the definition of µ(n), we write that µ(m) = ( 1) k and µ(n) = ( 1) s, and mn = p 1... p k q 1... q s, again using the definition of µ(n), we write µ(mn) = ( 1) k+s. Hence µ(mn) = ( 1) k+s = ( 1) k ( 1) s = µ(m)µ(n). Now suppose at least one of m and n is divisible by a square of a prime, then mn is also divisible by the square of a prime. So µ(mn) = 0 and µ(m) or µ(n) is equal to zero. Now it is clear to see that the product of µ(m) and µ(n) is equal to zero. So µ(mn) = µ(m)µ(n). On the other hand, from the definition of µ(n), we know that µ(4) = 0 because and µ(2) = 1. We can write that µ(4) = µ(2 2), but µ(4) = 0 µ(2)µ(2). Hence µ(n) is not completely multiplicative function. The Möbius function appears in many different places in number theory. One of its the most important properties is a formula for the divisor sum µ(d), extended over the positive divisor of n. It leads to Möbius inversion formula. 8
9 Theorem 2.2. For the Möbius function µ(n), the summatory function is defined by { 1 if n = 1 µ(d) = 0 if n > 1. We need the following theorem to prove Theorem 2.2. Theorem 2.3. If f is multiplicative function of n, and F is defined as follows F (n) = f(d) then F is also multiplicative function. Proof. We will show that F is multiplicative function. If F is multiplicative function, we write that when m and n are relatively numbers, then F (mn) = F (m)f (n). So, now let us choose (m, n) = 1. We have F (mn) = d mn f(d). Now, all divisiors of mn must be written as the product of relatively prime numbers. As we mentioned before, if F is multiplicative function, we write F (mn) = F (m)f (n) when (m, n) = 1. So we write d = d 1 d 2 as the product of relatively prime divisors d 1 of m and d 2 of n. Hence, we write F (mn) = d 1 m d 2 n f(d 1 d 2 ). Since f is multiplicative and since (d 1, d 2 ) = 1, we can write that F (mn) = d 1 m d 2 n f(d 1 )f(d 2 ) = d 1 m f(d 1 ) d 2 n f(d 2 ) = F (m)f (n). Now we continue to prove the Theorem 2.2. Proof. Consider, n = 1. It is clear to see that µ(d) = µ(d) = µ(1) = 1. d 1 9
10 Now we assume this formula for n > 1. Let us define an arithmetic function M as M(n) = µ(d). The Möbius function is multiplicative, then M(n) is multiplicative by Theorem 2.3. Let s suppose that n which is the product of powers of r different relatively prime numbers such that n = r i=1 p a i i. Then the results which are under the function of M are equal. So we write M(n) = r i=1 M(p a i i ). Now we are searching what is the result of M(n). If we find the result of M(p a i i ), we find the result of M(n). Now we can write that M(pa i i ) = d p a i µ(d) using the Theorem 2.3, which is the way to find the result. We i have M(p a i i ) = µ(d) d p a i i = µ(1) + µ(p i ) + µ(p 2 i ) + + µ(p a i i ) = 1 + ( 1) = 0. For every integer bigger than 1, we proved that the sum function of Möbius function is equal to zero. The another example of an arithmetic function is Euler s function. It is also a multiplicative function. 2.2 The Euler Function The function was introduced by Euler, in 1760, and is denoted by ϕ. This function is multiplicative which is one of the most important function in number theory. Definition 2.6. The Euler function ϕ(n) is the number of positive integers less than n which are relatively prime to n. 10
11 Example 3. Here is some values of ϕ(n). ϕ(1) = 1, ϕ(2) = 1, ϕ(3) = 2, ϕ(4) = 2, ϕ(5) = 4 ϕ(6) = 2, ϕ(7) = 6, ϕ(8) = 4, ϕ(9) = 6, ϕ(10) = 4 Now we find the values of the phi-function at primes powers. Theorem 2.4. Let p be a prime number. Then ϕ(p α ) = p α p α 1. Proof. Between 1 and p α there are p α integers. There are some numbers which are not relatively prime to p α, they are p, 2p,..., p α 1. There are exactly p α 1 such integers. So there are p α p α 1 integers less than p α that are relatively prime to p α. Hence, ϕ(p α ) = p α p α 1. Theorem 2.5. If p is a prime, then ϕ(p) = p 1. Proof. It is easy to see that from Theorem 2.4. Now we suppose α = 1 then ϕ(p α ) = p α p α 1 = p 1 p 1 1 = p 1. Example 4. We calculate the values of ϕ(n) for some prime numbers. ϕ(5 3 ) = = 100 ϕ(2 10 ) = = 512 ϕ(11 2 ) = = 110 The Euler s ϕ function is multiplicative function. If you re interested in proof of ϕ is multiplicative function, please read [3, 5, 7]. Example 5. Let s calculate ϕ(756) using that the Euler s ϕ function is multiplicative. This number can ben be written as 756 = Hence ϕ(756) = ϕ( ). We know that ϕ function is multiplicative. So we write ϕ(756) = ϕ(2 2 ) ϕ(3 3 ) ϕ(7). Using the Theorem 2.4 and Theorem 2.5, we find ϕ(2 2 ) = = 2, 11
12 So ϕ(3 3 ) = = 18, ϕ(7) = 7 1 = 6. ϕ(756) = = 216. Now we get the result. If you want to check more examples, read [5]. Theorem 2.6. For every positive integers d and n, we have ϕ(d) = n. Proof. We will prove this by induction on the number of different prime factors. We consider the case n = p α, where p is a prime number. We have ϕ(d) = ϕ(d) = ϕ(1) + ϕ(p) + ϕ(p 2 ) + + ϕ(p α ) d p α = 1 + (p 1) + (p 2 p) + + (p α p α 1 ) = p α = n. Correspondingly, now suppose that the theorem holds for integers with k distinct prime factors. Let us take any integer N with k +1 distinct prime factors and p α be the highest power of p that divides N. Now we write N = p α n where p and n are relatively prime numbers (i.e., (p,n)=1). We know when d ranges over the divisor of n, the set d, dp, dp 2,..., dp α ranges over the divisors of N. Then d N ϕ(d) = = ϕ(d) + ϕ(d) + ϕ(dp) + ϕ(d)ϕ(p) + ϕ(dp 2 ) + + ϕ(dp α ) ϕ(d)ϕ(p 2 ) + + ϕ(d)ϕ(p α ) = ϕ(d)[1 + ϕ(p) + ϕ(p 2 ) + + ϕ(p α )] = = np α = N. ϕ(d) e p α ϕ(e) We showed that ϕ(d) = n is true for every positive integers n, and d ranges over n. 12
13 Example 6. We give an example to understand the Theorem 2.6. ϕ(d) = ϕ(1) + ϕ(2) + ϕ(3) + ϕ(4) + ϕ(6) + ϕ(12) d 12 = = 12. REMARK: As ϕ is an arithmetic function, we note that ϕ(d) = ϕ( n d ). Now we show that for any multiplicative functions: If f is multiplicative function and not equal to zero, then f(d) or, equivalently, f(n d) denotes the sum of the values of a function f where d ranges over the positive divisors of n. We write that f(d) = f(n d) because since d ranges over n, n d ranges over n. For example; f(d) = f(1) + f(2) + f(3) + f(6) + f(9) + f(18) d 18 d 18 f( n d ) = f(18 1 ) + f(18 2 ) + f(18 3 ) + f(18 6 ) + f(18 9 ) + f(18 18 ) = f(18) + f(9) + f(6) + f(3) + f(2) + f(1) 2.3 Möbius Inversion Formula Theorem 2.7. If g is any arithmetic function and f is the sum function of g, so that f(n) = g(d) then g(n) = f(d)µ( n d ). Equivalently, if d ranges over n, n d ranges over n. Hence, we can write f(d)µ( n d ) = f( n d )µ(d). 13
14 Proof. The equality f(d)µ( n d ) = f( n d )µ(d) is true from the remark. If, we write n = ed from the definition (divisibility), where e is in Z. Now let us take n = de, so e = n d. Then the previous sum can be written as f(d)µ(e) de=n and it is possible to write the last sum as, f(e)µ(d). de=n Now we must prove that the sum f(d)µ( n d ) is equal to g(n) or, equivalentely, the sum f(n d )µ(d) is equal to g(n). Using equality below we write that f( n d ) = e n d g(e) µ(d)f( n d ) = (µ(d) e n d g(e)). Since e divides n d, then e divides n. Inversely, each divisor of n is e which divides n d if and only if d divides n e. So d divides n. As have seen, the coefficent of g(e) is d n µ(n) can be written as e µ(n) = d n e { 1 if n e = 1 0 if n e > 1 using the Theorem 2.2. That implies g(n) has only one coefficient g(e) which is not equal to zero. So g(e) = 1. Then g(n) = f( n d )µ(d). The Euler function is related to the Möbius function through the following formula. 14
15 Theorem 2.8. ϕ(n) = n µ(d) d where ϕ(n) is Euler s ϕ function. Proof. We know ϕ(d) = n from the Theorem 2.6. Take a function F which is the sum of the Euler s ϕ function is as F (n) = ϕ(d) = n. Use the Möbius inversion formula here ϕ(n) = F (d)µ( n d ) = = F ( n d )µ(d) n d µ(d) = n µ(d) d. Example 7. Let s calculate the value of ϕ(756), using Theorem 2.8. The divisors of this number are 1, 2, 3, 4, 7, 9, 12, 14, 18, 21, 27, 28, 36, 42, 54, 63, 84, 108, 126, 189, 252, 378, and 756. Now using the Theorem 2.8 we can calculate ϕ(756). ϕ(756) = n µ(d) d = 756 d 756 µ(d) d And here is some values of µ(n). = n d µ(d) ( µ(1) = µ(2) + + µ(378) + µ(756) ) µ(1) = 1, µ(2) = 1, µ(3) = 1, µ(6) = 1, 15
16 µ(7) = 1, µ(14) = 1, µ(21) = 1, µ(42) = 1. The value µ of the other numbers are equal to zero, because these numbers are divisible by a square larger than 1. Hence ( ) = = 216 We solved same example using by ϕ function is a multiplicative function. That way is easy and short, because if you want to use the Theorem 2.8, you should know that the values of µ function. 3 Cyclotomic Polynomials and Roots of Unity 3.1 nth Root of Unity Assume that a be an nth root of a number b, this means that b n = a. In particular the square root of 1 is 1 because 1 1 = 1, but ( 1)( 1) = 1, so 1 also a square root of 1. There are two square roots of 1. If we take the cube root of 1, then 1 is not a solution because ( 1)( 1)( 1) = 1. So 1 has only one solution if we study on real numbers, but in the complex numbers, there are three roots of 1. All cube roots of 1 can also be defined as powers of the negative interval. We see them below 16
17 REMARK: Let n be an integer and x be a complex number (and, in particular, a real number), the Euler s function states that e i(nx) = cos(nx) + isin(nx). C be the field of complex numbers, there are exactly n different nth roots of 1. If you divide the unit circle into n equal parts, using n points, it is easy to find them. Definition 3.1. A complex number z is called an nth root of unity for a positive integer n, if z n = 1. We will show that z n = 1. Let s take any complex number z. If we write this complex number on the polar coordinates, we get If we take the nth power of z, z = cosθ + isinθ. z n = (cosθ + isinθ) n = cos(n θ) + isin(n θ). We can write this equality, because this is de Moivre s formula. So z n = 1 cos(n θ) + isin(n θ) = cos(0) + isin(0). 17
18 Then nθ = 0 + 2kπ, where k = 0, 1,..., n 1. Thus θ = 2kπ n. The roots of unity is then in e 2πi/n for k = 0, 1,..., n 1. There are n different solutions for z n = 1, namely, e 2πi/n, e 2πi2/n,..., e 2πin/n. We usually assume that ζ n = e 2πi/n so that ζ n, ζ 2 n,..., ζ n n are the nth roots of z n = 1. Definition 3.2. An nth root of unity is primitive if it is of the form ζ k n with k and n relatively prime numbers, i.e., (k, n) = 1. If ζ n is a primitive nth root of unity and (ζ k n) m = 1 then n m. If you want to read more details, check [6]. 3.2 Cyclotomic Polynomials Definition 3.3. Let n be a positive integer and let ζn k be the primitive nth root of unity ( ζ n is the complex number e 2πi/n ). The nth cyclotomic polynomial Φ n (x) is Φ n (x) = (x ζn) k 1 k n gcd(n,k)=1 whose roots are the primitive nth roots of unity. Theorem 3.1. Let n be a positive integer. Then x n 1 = Φ d (x) where d ranges over the divisor of n. Proof. The roots of x n 1 are exactly nth roots of unity. On the other hand, if ζ is an nth root of unity and the order of ζ is d, then ζ is a primitive dth root of unity. So ζ is a root of Φ d (x). But, so ζ is a root of the right hand side. It follows that the polynomials on the left and right hand side have the same roots. Thus they are equal. Another way to find the nth cyclotomic polynomial: If n > 1, then Φ n (x) = xn 1 d Φ d(x) where d ranges over, except n, the divisor of n. (2) If you want to see more detail about cyclotomic polynomials, check [4, 10]. 18
19 Example 8. Here is some value of cyclotomic polynomials. Φ 1 (x) = x 1 Φ 2 (x) = x2 1 Φ 1 (x) = x2 1 x 1 = x + 1 Φ 3 (x) = x3 1 Φ 1 (x) = x3 1 x 1 = x2 + x + 1 Φ 4 (x) = x4 1 Φ 1 (x)φ 2 (x) = x2 + 1 Φ 5 (x) = x5 1 Φ 1 (x) = x4 + x 3 + x 2 + x + 1 Φ 6 (x) = x 6 1 Φ 1 (x)φ 2 (x)φ 3 (x) = x2 x + 1 Now we know that x n 1 = Φ d(x), and conversely, by using the Möbius function, we can write the following theorem. Theorem 3.2. Let n be a positive integer and µ(n) denotes the Möbius function. Then Φ n (x) = (x d 1) µ( n d ). Proof. To prove this formula, first we use the equality x n 1 = Φ d(x), then we take complex logarithm of this equality, and finally use the Möbius inversion formula. We have x n 1 = Φ d (x). Now take the complex logarithm both side of equality. It doesn t effect to the equality. log(x n 1) = log Φ d (x) Let s assume d = {d 1, d 2,..., d s }, where d i s are divisor of n and are not equal to n. log Φ d (x) = log (Φ d1 (x) Φ d2 (x) Φ ds (x)) 19
20 Using the property of logarithm, we write log (Φ d1 (x) Φ d2 (x) Φ ds (x)) = log(φ d1 (x)) + log(φ d2 (x)) + + log(φ ds (x)) = log(φ d (x)). Using Möbius inversion formula, we can write log(φ n (x)) = µ( n ) (log(x d ) d 1) = (log(x d 1) µ( n )) d = log((x d 1 1) µ( n ) d 1 ) + log((x d 2 1) µ( n ) d 2 ) + + log((x d s 1) µ( n ds ) ) = log ((x d 1 1) µ( n ) d 1 (x d 2 1) µ( n ) d 2 (x d s 1) µ( n )) ds = log (x d 1) µ( n d ) If we cancel out the logarithm, we get the result Φ n (x) = (x d 1) µ( n d ). Now we can see the connection between Möbius inversion formula and cyclotomic polynomials. When x n 1 = Φ d (x), it is possible to write that Φ n (x) = (x d 1) µ( n d ). Example 9. We are going to find cyclotomic polynomials using the formula Φ n (x) = (x d 1) µ( n d ) for n = 1, 2,..., 20. Φ 1 (x) = x 1 Φ 2 (x) = x + 1 Φ 3 (x) = x 2 + x
21 Φ 4 (x) = x Φ 5 (x) = x 4 + x 3 + x 2 + x + 1 Φ 6 (x) = x 2 x + 1 Φ 7 (x) = x 6 + x 5 + x 4 + x 3 + x 2 + x + 1 Φ 8 (x) = x Φ 9 (x) = x 6 + x Φ 10 (x) = x 4 x 3 + x 2 x + 1 Φ 11 (x) = x 10 + x 9 + x 8 + x 7 + x 6 + x 5 + x 4 + x 3 + x 2 + x + 1 Φ 12 (x) = x 4 x Φ 13 (x) = x 12 + x 11 + x 10 + x 9 + x 8 + x 7 + x 6 + x 5 + x 4 + x 3 + x 2 + x + 1 Φ 14 (x) = x 6 x 5 + x 4 x 3 + x 2 x + 1 Φ 15 (x) = x 8 x 7 + x 5 x 4 + x 3 x + 1 Φ 16 (x) = x 8 1 Φ 17 (x) = x 16 + x 15 + x 14 + x 13 + x 12 + x 11 + x 10 + x 9 + x 8 + x 7 + x 6 + x 5 + x 4 + x 3 + x 2 + x + 1 Φ 18 (x) = x 6 x Φ 19 (x) = x 18 + x 17 + x 16 + x 15 + x 14 + x 13 + x 12 + x 11 + x 10 + x 9 + x 8 + x 7 + x 6 + x 5 + x 4 + x 3 + x 2 + x + 1 Φ 20 (x) = x 8 x 6 + x 4 x We have already found some cyclotomic polynomials in example 8. In this example you don t need to know values of Möbius function. If you want to find cyclotomic polynomials using the Theorem 3.2, you should know the values of Möbius function. As have seen, the coefficients of cyclotomic polynomial are often 1, 0 and 1, but for n 105 some coefficients are different from this set. For example n = 105, then Φ 105 (x) =x 48 + x 47 + x 46 x 43 x 42 2x 41 x 40 x 39 + x 36 + x 35 + x 34 + x 33 + x 32 + x 31 x 28 x 26 x 24 x 22 x 20 + x 17 + x 16 + x 15 + x 14 + x 13 + x 12 x 9 x 8 2x 7 x 6 x 5 + x 2 + x + 1. We see that there is a coefficient 2 which is not included in { 1, 0, 1}. Theorem 3.3. The coefficients of Φ n (x) are integers. Proof. We prove it using inductive method. Clearly, Φ 1 (x) = x 1 Z[x]. Now we suppose that, for k < n, the coefficients of Φ n (x) are integers. Let f(x) = Φ d (x). Then we say that f(x) Z[x], from the inductive d<n method. Using the formula (2), we write if Φ n (x) = xn 1 f(x) 21
22 then x n 1 = Φ n (x)f(x) On the other hand, x n 1 Z[x]. Also using the division algorithm, we can write x n 1 = f(x)g(x) + r(x) for some g(x), r(x) Z[x]. By the uniqueness, we take r(x) = 0. So x n 1 = f(x)g(x). It is easy to see g(x) = Φ n (x). Since g(x) Z[x], Φ n (x) Z[x]. Finally we say that the coefficients of Φ n (x) are integers. 22
23 4 Conclusion In this study, the Möbius inversion formula has been introduced and proved. The roots of unity and cyclotomic polynomials have been introduced. In the first cheapter, some informations about Möbius function, Euler s ϕ function, Möbius inversion formula, roots of unity and cyclotomic polynomials have been introduced. And also some definitions which will be used in the next cheapters have been mentioned. In the second cheapter, some arithmetic functions and properties of these functions have been studied. The Möbius function which is defined on arithmetic functions, has been studied. The Euler s ϕ function and its applications have been mentioned. The Möbius inversion formula has been introduced. A theorem which is related with Euler s ϕ function and µ function, using Möbius inversion formula, has been proved, that is ϕ(n) = n µ(d) d. In the third cheapter, the roots of unity in the complex numbers have been introduced. Accordingly, the primitive roots of unity have been introduced. Later, the cyclotomic polynomials whose roots are the primitive nth roots of unity, have been investigated. Accordingly, the connection between Möbius inversion formula and cyclotomic polynomials has been shown. The connection between Möbius inversion formula and cyclotomic polynomials in the complex numbers has been shown. Since this is the formula below, x n 1 = Φ d (x). and with the Möbius inversion formula and using the complex logarithm Φ n (x) = (x d 1) µ( n d ) has been proved. 23
24 References [1] L. E. Dickson, History of the theory of numbers, Vol. I, Divisibility and Primality, Chelsea Publishing Company, New York (1992) [2] Gareth A. Jones and J. Mary Jones, Elementary number theory, Springer-Verlag London Limited (1998) [3] H. E. Rose, A course in number theory, Oxford University Press, New York, second edition (1994) [4] I. N. Herstein, Abstract algebra, Prentice-Hall, Inc., third edition (1996) [5] J. H. Silverman, A friendly introduction to number theory, Prentice- Hall, Inc., second edition (2001) [6] B. L. van der Waerden, Algebra, Vol. I, Springer-Verlag New york, Inc., (1991) [7] K. H. Rosen, Elementary number theory and its applications, Assison- Wesley Publishing Company, third edition (1993) [8] I. Niven, H. S. Zuckerman, An introduction to the theory of numbers, John Wiley & Sons, Inc., second edition (1967) [9] G. H. Hardy, E. M. Wright, An introduction to the theory of number, Oxford University Press, Oxford, second edition (2008) [10] T. Nagell, Introduction to number theory, Almqvist-Wiksell, Sweden (1951) [11] K. Ireland, M. Rosen, A classic introduction to modern number theory, Springer-Verlag, New York (1982) [12] N. Lauritzen, Concrete abstract algebra: from numbers to Gröbner bases, Cambridge University Press, New York, USA (2003) [13] I. S. Luthar, I. B. S. Passi, Algebra, Vol. 4, Field Theory, Alpha Science International Ltd., Harrow, U.K. (2004) [14] W. J. LeVeque, Topics in number theory, Vol. I, Addison-Wesley Publishing Company (1956) 24
25 SE Växjö / SE Kalmar Tel dfm@lnu.se Lnu.se/dfm
Elementary Properties of Cyclotomic Polynomials
Elementary Properties of Cyclotomic Polynomials Yimin Ge Abstract Elementary properties of cyclotomic polynomials is a topic that has become very popular in Olympiad mathematics. The purpose of this article
More informationSummary Slides for MATH 342 June 25, 2018
Summary Slides for MATH 342 June 25, 2018 Summary slides based on Elementary Number Theory and its applications by Kenneth Rosen and The Theory of Numbers by Ivan Niven, Herbert Zuckerman, and Hugh Montgomery.
More informationSmol Results on the Möbius Function
Karen Ge August 3, 207 Introduction We will address how Möbius function relates to other arithmetic functions, multiplicative number theory, the primitive complex roots of unity, and the Riemann zeta function.
More informationZsigmondy s Theorem. Lola Thompson. August 11, Dartmouth College. Lola Thompson (Dartmouth College) Zsigmondy s Theorem August 11, / 1
Zsigmondy s Theorem Lola Thompson Dartmouth College August 11, 2009 Lola Thompson (Dartmouth College) Zsigmondy s Theorem August 11, 2009 1 / 1 Introduction Definition o(a modp) := the multiplicative order
More informationDivisibility. 1.1 Foundations
1 Divisibility 1.1 Foundations The set 1, 2, 3,...of all natural numbers will be denoted by N. There is no need to enter here into philosophical questions concerning the existence of N. It will suffice
More informationPart II. Number Theory. Year
Part II Year 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2017 Paper 3, Section I 1G 70 Explain what is meant by an Euler pseudoprime and a strong pseudoprime. Show that 65 is an Euler
More informationThe least prime congruent to one modulo n
The least prime congruent to one modulo n R. Thangadurai and A. Vatwani September 10, 2010 Abstract It is known that there are infinitely many primes 1 (mod n) for any integer n > 1. In this paper, we
More informationSection X.55. Cyclotomic Extensions
X.55 Cyclotomic Extensions 1 Section X.55. Cyclotomic Extensions Note. In this section we return to a consideration of roots of unity and consider again the cyclic group of roots of unity as encountered
More informationThe primitive root theorem
The primitive root theorem Mar Steinberger First recall that if R is a ring, then a R is a unit if there exists b R with ab = ba = 1. The collection of all units in R is denoted R and forms a group under
More informationMath 314 Course Notes: Brief description
Brief description These are notes for Math 34, an introductory course in elementary number theory Students are advised to go through all sections in detail and attempt all problems These notes will be
More informationA Generalization of Wilson s Theorem
A Generalization of Wilson s Theorem R. Andrew Ohana June 3, 2009 Contents 1 Introduction 2 2 Background Algebra 2 2.1 Groups................................. 2 2.2 Rings.................................
More informationTheory of Numbers Problems
Theory of Numbers Problems Antonios-Alexandros Robotis Robotis October 2018 1 First Set 1. Find values of x and y so that 71x 50y = 1. 2. Prove that if n is odd, then n 2 1 is divisible by 8. 3. Define
More informationAny real-valued function on the integers f:n R (or complex-valued function f:n C) is called an arithmetic function.
Arithmetic Functions Any real-valued function on the integers f:n R (or complex-valued function f:n C) is called an arithmetic function. Examples: τ(n) = number of divisors of n; ϕ(n) = number of invertible
More informationϕ : Z F : ϕ(t) = t 1 =
1. Finite Fields The first examples of finite fields are quotient fields of the ring of integers Z: let t > 1 and define Z /t = Z/(tZ) to be the ring of congruence classes of integers modulo t: in practical
More informationSection V.8. Cyclotomic Extensions
V.8. Cyclotomic Extensions 1 Section V.8. Cyclotomic Extensions Note. In this section we explore splitting fields of x n 1. The splitting fields turn out to be abelian extensions (that is, algebraic Galois
More informationGALOIS THEORY. Contents
GALOIS THEORY MARIUS VAN DER PUT & JAAP TOP Contents 1. Basic definitions 1 1.1. Exercises 2 2. Solving polynomial equations 2 2.1. Exercises 4 3. Galois extensions and examples 4 3.1. Exercises. 6 4.
More informationCYCLOTOMIC POLYNOMIALS
CYCLOTOMIC POLYNOMIALS 1. The Derivative and Repeated Factors The usual definition of derivative in calculus involves the nonalgebraic notion of limit that requires a field such as R or C (or others) where
More informationNumber-Theoretic Function
Chapter 1 Number-Theoretic Function 1.1 The function τ and σ Definition 1.1.1. Given a positive integer n, let τ(n) denote the number of positive divisor of n and σ(n) denote the sum of these divisor.
More informationElementary Number Theory Review. Franz Luef
Elementary Number Theory Review Principle of Induction Principle of Induction Suppose we have a sequence of mathematical statements P(1), P(2),... such that (a) P(1) is true. (b) If P(k) is true, then
More informationLECTURE 4: CHINESE REMAINDER THEOREM AND MULTIPLICATIVE FUNCTIONS
LECTURE 4: CHINESE REMAINDER THEOREM AND MULTIPLICATIVE FUNCTIONS 1. The Chinese Remainder Theorem We now seek to analyse the solubility of congruences by reinterpreting their solutions modulo a composite
More informationTrifectas in geometric progression
189 Trifectas in geometric progression Gerry Myerson Abstract The trifecta in the 2007 Melbourne Cup was the numbers 6 12 24, a geometric progression. How many trifectas in geometric progression are there
More informationModular Arithmetic. Examples: 17 mod 5 = 2. 5 mod 17 = 5. 8 mod 3 = 1. Some interesting properties of modular arithmetic:
Modular Arithmetic If a mod n = b, then a = c n + b. When you reduce a number a modulo n you usually want 0 b < n. Division Principle [Bar02, pg. 61]: Let n be a positive integer and let a be any integer.
More informationCYCLOTOMIC POLYNOMIALS
CYCLOTOMIC POLYNOMIALS 1. The Derivative and Repeated Factors The usual definition of derivative in calculus involves the nonalgebraic notion of limit that requires a field such as R or C (or others) where
More informationRoots of Unity, Cyclotomic Polynomials and Applications
Swiss Mathematical Olympiad smo osm Roots of Unity, Cyclotomic Polynomials and Applications The task to be done here is to give an introduction to the topics in the title. This paper is neither complete
More informationFinite fields Michel Waldschmidt
Finite fields Michel Waldschmidt http://www.imj-prg.fr/~michel.waldschmidt//pdf/finitefields.pdf Updated: 03/07/2018 Contents 1 Background: Arithmetic 1.1 Cyclic groups If G is a finite multiplicative
More informationDIRICHLET S THEOREM ON PRIMES IN ARITHMETIC PROGRESSIONS. 1. Introduction
DIRICHLET S THEOREM ON PRIMES IN ARITHMETIC PROGRESSIONS INNA ZAKHAREVICH. Introduction It is a well-known fact that there are infinitely many rimes. However, it is less clear how the rimes are distributed
More informationQuasi-reducible Polynomials
Quasi-reducible Polynomials Jacques Willekens 06-Dec-2008 Abstract In this article, we investigate polynomials that are irreducible over Q, but are reducible modulo any prime number. 1 Introduction Let
More informationUNDERSTANDING RULER AND COMPASS CONSTRUCTIONS WITH FIELD THEORY
UNDERSTANDING RULER AND COMPASS CONSTRUCTIONS WITH FIELD THEORY ISAAC M. DAVIS Abstract. By associating a subfield of R to a set of points P 0 R 2, geometric properties of ruler and compass constructions
More informationCONSTRUCTIBLE NUMBERS AND GALOIS THEORY
CONSTRUCTIBLE NUMBERS AND GALOIS THEORY SVANTE JANSON Abstract. We correct some errors in Grillet [2], Section V.9. 1. Introduction The purpose of this note is to correct some errors in Grillet [2], Section
More informationarxiv: v3 [math.nt] 15 Dec 2016
Lehmer s totient problem over F q [x] arxiv:1312.3107v3 [math.nt] 15 Dec 2016 Qingzhong Ji and Hourong Qin Department of Mathematics, Nanjing University, Nanjing 210093, P.R.China Abstract: In this paper,
More informationA Note on Cyclotomic Integers
To the memory of Alan Thorndike, former professor of physics at the University of Puget Sound and a dear friend, teacher and mentor. A Note on Cyclotomic Integers Nicholas Phat Nguyen 1 Abstract. In this
More informationConcrete Mathematics: A Portfolio of Problems
Texas A&M University - San Antonio Concrete Mathematics Concrete Mathematics: A Portfolio of Problems Author: Sean Zachary Roberson Supervisor: Prof. Donald Myers July, 204 Chapter : Recurrent Problems
More informationGAPS IN BINARY EXPANSIONS OF SOME ARITHMETIC FUNCTIONS, AND THE IRRATIONALITY OF THE EULER CONSTANT
Journal of Prime Research in Mathematics Vol. 8 202, 28-35 GAPS IN BINARY EXPANSIONS OF SOME ARITHMETIC FUNCTIONS, AND THE IRRATIONALITY OF THE EULER CONSTANT JORGE JIMÉNEZ URROZ, FLORIAN LUCA 2, MICHEL
More information18.785: Analytic Number Theory, MIT, spring 2006 (K.S. Kedlaya) Dirichlet series and arithmetic functions
18.785: Analytic Number Theory, MIT, spring 2006 (K.S. Kedlaya) Dirichlet series and arithmetic functions 1 Dirichlet series The Riemann zeta function ζ is a special example of a type of series we will
More informationABSTRACT. AMBROSINO, MARY ELIZABETH. Maximum Gap of (Inverse) Cyclotomic Polynomials. (Under the direction of Hoon Hong.)
ABSTRACT AMBROSINO, MARY ELIZABETH. Maximum Gap of (Inverse) Cyclotomic Polynomials. (Under the direction of Hoon Hong.) The cyclotomic polynomial Φ n is the monic polynomial whose zeroes are the n-th
More informationarxiv:math/ v1 [math.nt] 9 Aug 2004
arxiv:math/0408107v1 [math.nt] 9 Aug 2004 ELEMENTARY RESULTS ON THE BINARY QUADRATIC FORM a 2 + ab + b 2 UMESH P. NAIR Abstract. This paper examines with elementary proofs some interesting properties of
More informationON VALUES OF CYCLOTOMIC POLYNOMIALS. V
Math. J. Okayama Univ. 45 (2003), 29 36 ON VALUES OF CYCLOTOMIC POLYNOMIALS. V Dedicated to emeritus professor Kazuo Kishimoto on his seventieth birthday Kaoru MOTOSE In this paper, using properties of
More information1 Spring 2002 Galois Theory
1 Spring 2002 Galois Theory Problem 1.1. Let F 7 be the field with 7 elements and let L be the splitting field of the polynomial X 171 1 = 0 over F 7. Determine the degree of L over F 7, explaining carefully
More informationGalois Theory, summary
Galois Theory, summary Chapter 11 11.1. UFD, definition. Any two elements have gcd 11.2 PID. Every PID is a UFD. There are UFD s which are not PID s (example F [x, y]). 11.3 ED. Every ED is a PID (and
More informationSEVERAL PROOFS OF THE IRREDUCIBILITY OF THE CYCLOTOMIC POLYNOMIALS
SEVERAL PROOFS OF THE IRREDUCIBILITY OF THE CYCLOTOMIC POLYNOMIALS STEVEN H. WEINTRAUB ABSTRACT. We present a number of classical proofs of the irreducibility of the n-th cyclotomic polynomial Φ n (x).
More information1. Given the public RSA encryption key (e, n) = (5, 35), find the corresponding decryption key (d, n).
MATH 135: Randomized Exam Practice Problems These are the warm-up exercises and recommended problems taken from all the extra practice sets presented in random order. The challenge problems have not been
More informationNewton, Fermat, and Exactly Realizable Sequences
1 2 3 47 6 23 11 Journal of Integer Sequences, Vol. 8 (2005), Article 05.1.2 Newton, Fermat, and Exactly Realizable Sequences Bau-Sen Du Institute of Mathematics Academia Sinica Taipei 115 TAIWAN mabsdu@sinica.edu.tw
More informationContents. 4 Arithmetic and Unique Factorization in Integral Domains. 4.1 Euclidean Domains and Principal Ideal Domains
Ring Theory (part 4): Arithmetic and Unique Factorization in Integral Domains (by Evan Dummit, 018, v. 1.00) Contents 4 Arithmetic and Unique Factorization in Integral Domains 1 4.1 Euclidean Domains and
More informationPart IA. Numbers and Sets. Year
Part IA Year 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2017 19 Paper 4, Section I 1D (a) Show that for all positive integers z and n, either z 2n 0 (mod 3) or
More informationExplicit Methods in Algebraic Number Theory
Explicit Methods in Algebraic Number Theory Amalia Pizarro Madariaga Instituto de Matemáticas Universidad de Valparaíso, Chile amaliapizarro@uvcl 1 Lecture 1 11 Number fields and ring of integers Algebraic
More informationSome properties and applications of a new arithmetic function in analytic number theory
NNTDM 17 (2011), 3, 38-48 Some properties applications of a new arithmetic function in analytic number theory Ramesh Kumar Muthumalai Department of Mathematics, D.G. Vaishnav College Chennai-600 106, Tamil
More informationD-MATH Algebra II FS18 Prof. Marc Burger. Solution 26. Cyclotomic extensions.
D-MAH Algebra II FS18 Prof. Marc Burger Solution 26 Cyclotomic extensions. In the following, ϕ : Z 1 Z 0 is the Euler function ϕ(n = card ((Z/nZ. For each integer n 1, we consider the n-th cyclotomic polynomial
More informationOn the Prime Divisors of Odd Perfect Numbers
On the Prime Divisors of Odd Perfect Numbers Justin Sweeney Department of Mathematics Trinity College Hartford, CT justin.sweeney@trincoll.edu April 27, 2009 1 Contents 1 History of Perfect Numbers 5 2
More informationGauss and Riemann versus elementary mathematics
777-855 826-866 Gauss and Riemann versus elementary mathematics Problem at the 987 International Mathematical Olympiad: Given that the polynomial [ ] f (x) = x 2 + x + p yields primes for x =,, 2,...,
More informationDONG QUAN NGOC NGUYEN
REPRESENTATION OF UNITS IN CYCLOTOMIC FUNCTION FIELDS DONG QUAN NGOC NGUYEN Contents 1 Introduction 1 2 Some basic notions 3 21 The Galois group Gal(K /k) 3 22 Representation of integers in O, and the
More informationMathematical Journal of Okayama University
Mathematical Journal of Okayama University Volume 48, Issue 1 2006 Article 1 JANUARY 2006 On Euclidean Algorithm Kaoru Motose Hirosaki University Copyright c 2006 by the authors. Mathematical Journal of
More informationA connection between number theory and linear algebra
A connection between number theory and linear algebra Mark Steinberger Contents 1. Some basics 1 2. Rational canonical form 2 3. Prime factorization in F[x] 4 4. Units and order 5 5. Finite fields 7 6.
More information1, for s = σ + it where σ, t R and σ > 1
DIRICHLET L-FUNCTIONS AND DEDEKIND ζ-functions FRIMPONG A. BAIDOO Abstract. We begin by introducing Dirichlet L-functions which we use to prove Dirichlet s theorem on arithmetic progressions. From there,
More informationA PROBLEM ON THE CONJECTURE CONCERNING THE DISTRIBUTION OF GENERALIZED FERMAT PRIME NUMBERS (A NEW METHOD FOR THE SEARCH FOR LARGE PRIMES)
A PROBLEM ON THE CONJECTURE CONCERNING THE DISTRIBUTION OF GENERALIZED FERMAT PRIME NUMBERS A NEW METHOD FOR THE SEARCH FOR LARGE PRIMES) YVES GALLOT Abstract Is it possible to improve the convergence
More informationAn arithmetical equation with respect to regular convolutions
The final publication is available at Springer via http://dx.doi.org/10.1007/s00010-017-0473-z An arithmetical equation with respect to regular convolutions Pentti Haukkanen School of Information Sciences,
More informationObjective Type Questions
DISTANCE EDUCATION, UNIVERSITY OF CALICUT NUMBER THEORY AND LINEARALGEBRA Objective Type Questions Shyama M.P. Assistant Professor Department of Mathematics Malabar Christian College, Calicut 7/3/2014
More informationarxiv: v1 [math.nt] 2 May 2011
Inequalities for multiplicative arithmetic functions arxiv:1105.0292v1 [math.nt] 2 May 2011 József Sándor Babeş Bolyai University Department of Mathematics Str. Kogălniceanu Nr. 1 400084 Cluj Napoca, Romania
More informationbut no smaller power is equal to one. polynomial is defined to be
13. Radical and Cyclic Extensions The main purpose of this section is to look at the Galois groups of x n a. The first case to consider is a = 1. Definition 13.1. Let K be a field. An element ω K is said
More information2 More on Congruences
2 More on Congruences 2.1 Fermat s Theorem and Euler s Theorem definition 2.1 Let m be a positive integer. A set S = {x 0,x 1,,x m 1 x i Z} is called a complete residue system if x i x j (mod m) whenever
More informationI(n) = ( ) f g(n) = d n
9 Arithmetic functions Definition 91 A function f : N C is called an arithmetic function Some examles of arithmetic functions include: 1 the identity function In { 1 if n 1, 0 if n > 1; 2 the constant
More informationMTH310 EXAM 2 REVIEW
MTH310 EXAM 2 REVIEW SA LI 4.1 Polynomial Arithmetic and the Division Algorithm A. Polynomial Arithmetic *Polynomial Rings If R is a ring, then there exists a ring T containing an element x that is not
More informationAlgebra Homework, Edition 2 9 September 2010
Algebra Homework, Edition 2 9 September 2010 Problem 6. (1) Let I and J be ideals of a commutative ring R with I + J = R. Prove that IJ = I J. (2) Let I, J, and K be ideals of a principal ideal domain.
More informationarxiv: v1 [math.ho] 12 Sep 2008
arxiv:0809.2139v1 [math.ho] 12 Sep 2008 Constructing the Primitive Roots of Prime Powers Nathan Jolly September 12, 2008 Abstract We use only addition and multiplication to construct the primitive roots
More informationProperties of Arithmetical Functions
Properties of Arithmetical Functions Zack Clark Math 336, Spring 206 Introduction Arithmetical functions, as dened by Delany [2], are the functions f(n) that take positive integers n to complex numbers.
More informationIntroduction to finite fields
Chapter 7 Introduction to finite fields This chapter provides an introduction to several kinds of abstract algebraic structures, particularly groups, fields, and polynomials. Our primary interest is in
More informationSolutions of exercise sheet 6
D-MATH Algebra I HS 14 Prof. Emmanuel Kowalski Solutions of exercise sheet 6 1. (Irreducibility of the cyclotomic polynomial) Let n be a positive integer, and P Z[X] a monic irreducible factor of X n 1
More informationOn the Coefficients of Cyclotomic Polynomials
310 On the Coefficients of Cyclotomic Polynomials R. Thangadurai 1. Properties of Cyclotomic Polynomials Cyclotomy is the process of dividing a circle into equal parts, which is precisely the effect obtained
More informationField Theory Qual Review
Field Theory Qual Review Robert Won Prof. Rogalski 1 (Some) qual problems ˆ (Fall 2007, 5) Let F be a field of characteristic p and f F [x] a polynomial f(x) = i f ix i. Give necessary and sufficient conditions
More informationReducibility of Polynomials over Finite Fields
Master Thesis Reducibility of Polynomials over Finite Fields Author: Muhammad Imran Date: 1976-06-02 Subject: Mathematics Level: Advance Course code: 5MA12E Abstract Reducibility of certain class of polynomials
More informationSection IV.23. Factorizations of Polynomials over a Field
IV.23 Factorizations of Polynomials 1 Section IV.23. Factorizations of Polynomials over a Field Note. Our experience with classical algebra tells us that finding the zeros of a polynomial is equivalent
More informationA talk given at the Institute of Mathematics (Beijing, June 29, 2008)
A talk given at the Institute of Mathematics (Beijing, June 29, 2008) STUDY COVERS OF GROUPS VIA CHARACTERS AND NUMBER THEORY Zhi-Wei Sun Department of Mathematics Nanjing University Nanjing 210093, P.
More informationAlgebraic trigonometric values at rational multipliers of π
ACTA ET COMMENTATIONES UNIVERSITATIS TARTUENSIS DE MATHEMATICA Volume, Number, June 04 Available online at http://acutm.math.ut.ee Algebraic trigonometric values at rational multipliers of π Pinthira Tangsupphathawat
More informationLECTURE NOTES IN CRYPTOGRAPHY
1 LECTURE NOTES IN CRYPTOGRAPHY Thomas Johansson 2005/2006 c Thomas Johansson 2006 2 Chapter 1 Abstract algebra and Number theory Before we start the treatment of cryptography we need to review some basic
More informationALGEBRA HW 9 CLAY SHONKWILER
ALGEBRA HW 9 CLAY SHONKWILER 1 Let F = Z/pZ, let L = F (x, y) and let K = F (x p, y p ). Show that L is a finite field extension of K, but that there are infinitely many fields between K and L. Is L =
More informationEULER S THEOREM KEITH CONRAD
EULER S THEOREM KEITH CONRAD. Introduction Fermat s little theorem is an important property of integers to a prime modulus. Theorem. (Fermat). For prime p and any a Z such that a 0 mod p, a p mod p. If
More informationSelberg s proof of the prime number theorem
Fall 20 Independent Study Selberg s proof of the prime number theorem Sana Jaber List of study units 000 0002 The notion of finite limit of a function at infinity. A first discussion of prime numbers.
More informationMathematics 4: Number Theory Problem Sheet 3. Workshop 26 Oct 2012
Mathematics 4: Number Theory Problem Sheet 3 Workshop 26 Oct 2012 The aim of this workshop is to show that Carmichael numbers are squarefree and have at least 3 distinct prime factors (1) (Warm-up question)
More informationProofs of the infinitude of primes
Proofs of the infinitude of primes Tomohiro Yamada Abstract In this document, I would like to give several proofs that there exist infinitely many primes. 0 Introduction It is well known that the number
More informationA Review Study on Presentation of Positive Integers as Sum of Squares
A Review Study on Presentation of Positive Integers as Sum of Squares Ashwani Sikri Department of Mathematics, S. D. College Barnala-148101 ABSTRACT It can be easily seen that every positive integer is
More information18. Cyclotomic polynomials II
18. Cyclotomic polynomials II 18.1 Cyclotomic polynomials over Z 18.2 Worked examples Now that we have Gauss lemma in hand we can look at cyclotomic polynomials again, not as polynomials with coefficients
More informationO.B. Berrevoets. On Lehmer s problem. Bachelor thesis. Supervisor: Dr J.H. Evertse. Date bachelor exam: 24 juni 2016
O.B. Berrevoets On Lehmer s problem Bachelor thesis Supervisor: Dr J.H. Evertse Date bachelor exam: 24 juni 2016 Mathematical Institute, Leiden University Contents 1 Introduction 2 1.1 History of the Mahler
More informationAn Approach to Hensel s Lemma
Irish Math. Soc. Bulletin 47 (2001), 15 21 15 An Approach to Hensel s Lemma gary mcguire Abstract. Hensel s Lemma is an important tool in many ways. One application is in factoring polynomials over Z.
More informationFinite Fields and Error-Correcting Codes
Lecture Notes in Mathematics Finite Fields and Error-Correcting Codes Karl-Gustav Andersson (Lund University) (version 1.013-16 September 2015) Translated from Swedish by Sigmundur Gudmundsson Contents
More informationFactorization in Integral Domains II
Factorization in Integral Domains II 1 Statement of the main theorem Throughout these notes, unless otherwise specified, R is a UFD with field of quotients F. The main examples will be R = Z, F = Q, and
More informationAn Introduction to Galois Theory. Andrew Baker
An Introduction to Galois Theory Andrew Baker [7/0/019] School of Mathematics & Statistics, University of Glasgow. Email address: a.baker@maths.gla.ac.uk URL: http://www.maths.gla.ac.uk/ ajb Q( 3, ζ 3
More informationMath 581: Skeleton Notes
Math 581: Skeleton Notes Bart Snapp June 7, 2010 Chapter 1 Rings Definition 1 A ring is a set R with two operations: + called addition and called multiplication such that: (i) (R,+) is an abelian group
More informationSome infinite series involving arithmetic functions
Notes on Number Theory and Discrete Mathematics ISSN 131 5132 Vol. 21, 215, No. 2, 8 14 Some infinite series involving arithmetic functions Ramesh Kumar Muthumalai Department of Mathematics, Saveetha Engineering
More informationTHE CYCLOTOMIC EQUATION AND ITS SIGNIFICANCE TO SOLVING THE QUINTIC EQUATION
THE CYCLOTOMIC EQUATION AND ITS SIGNIFICANCE TO SOLVING THE QUINTIC EQUATION Jay Villanueva Florida Memorial University Miami, FL 33055 jvillanu@fmuniv.edu ICTCM 2013 I. Introduction A. The cyclotomic
More informationNotes for 4H Galois Theory Andrew Baker
Notes for 4H Galois Theory 003 4 Andrew Baker [9/05/004] Department of Mathematics, University of Glasgow. E-mail address: a.baker@maths.gla.ac.uk URL: http://www.maths.gla.ac.uk/ ajb Introduction: What
More informationContinuing the pre/review of the simple (!?) case...
Continuing the pre/review of the simple (!?) case... Garrett 09-16-011 1 So far, we have sketched the connection between prime numbers, and zeros of the zeta function, given by Riemann s formula p m
More informationCyclotomic Polynomials in Olympiad Number Theory
Cyclotomic Polynomials in Olympiad Number Theory Lawrence Sun lala-sun@hotmail.com February 17, 2013 Abstract This is a paper discussing the powerful applications cyclotomic polynomials have in olympiad
More informationCYCLOTOMIC EXTENSIONS
CYCLOTOMIC EXTENSIONS KEITH CONRAD 1. Introduction For a positive integer n, an nth root of unity in a field is a solution to z n = 1, or equivalently is a root of T n 1. There are at most n different
More informationAn Additive Characterization of Fibers of Characters on F p
An Additive Characterization of Fibers of Characters on F p Chris Monico Texas Tech University Lubbock, TX c.monico@ttu.edu Michele Elia Politecnico di Torino Torino, Italy elia@polito.it January 30, 2009
More informationMath 121 Homework 3 Solutions
Math 121 Homework 3 Solutions Problem 13.4 #6. Let K 1 and K 2 be finite extensions of F in the field K, and assume that both are splitting fields over F. (a) Prove that their composite K 1 K 2 is a splitting
More informationNumber Theory in Cryptology
Number Theory in Cryptology Abhijit Das Department of Computer Science and Engineering Indian Institute of Technology Kharagpur October 15, 2011 What is Number Theory? Theory of natural numbers N = {1,
More informationProbabilistic Aspects of the Integer-Polynomial Analogy
Probabilistic Aspects of the Integer-Polynomial Analogy Kent E. Morrison Department of Mathematics California Polytechnic State University San Luis Obispo, CA 93407 kmorriso@calpoly.edu Zhou Dong Department
More informationMATH 431 PART 2: POLYNOMIAL RINGS AND FACTORIZATION
MATH 431 PART 2: POLYNOMIAL RINGS AND FACTORIZATION 1. Polynomial rings (review) Definition 1. A polynomial f(x) with coefficients in a ring R is n f(x) = a i x i = a 0 + a 1 x + a 2 x 2 + + a n x n i=0
More information1 The Galois Group of a Quadratic
Algebra Prelim Notes The Galois Group of a Polynomial Jason B. Hill University of Colorado at Boulder Throughout this set of notes, K will be the desired base field (usually Q or a finite field) and F
More informationMathematics 136 Calculus 2 Everything You Need Or Want To Know About Partial Fractions (and maybe more!) October 19 and 21, 2016
Mathematics 36 Calculus 2 Everything You Need Or Want To Know About Partial Fractions (and maybe more!) October 9 and 2, 206 Every rational function (quotient of polynomials) can be written as a polynomial
More information