Let q be a prime and let m and n be non-zero integers. Prove that if...
5. (a) Let m,n be coprime integers, and suppose a is an integer which is divisible by both m and n. Prove that mn divides a. (b) Show that the conclusion of part (a) is false if m and n are not coprime (ie, show that if m and n are not coprime, there exists an integer a such that mla and nla, but mn does not divide a). (c) Show that if hef(x,m) = 1 and hcf(y,m) = 1,...
Exercise 2. Let φ denote the Euler totient function. (i) Prove that for all positive integers m and n, if m,n are relatively prime (coprime), then φ(mn-o(m)o(n) (ii) Is the converse true? Prove or provide a counter-example.
8. (a) Prove that if p and q are prime numbers then p2 + pq is not a perfect square. (b) Prove that, for every integer a and every prime p, if p | a then ged(a,pb) = god(a,b). Is the converse of this statement true? Explain why or why not. (c) Prove that, for every non-zero integer n, the sum of all (positive or negative) divisors of n is equal to zero. 9. Let a and b be integers...
If m and n are coprime positive integers, prove that φ(n) no(m)-1 (mod mn).
Let P, Q ∈ Z[x]. Prove that P and Q are relatively prime in Q[x] if and only if the ideal (P, Q) of Z[x] generated by P and Q contains a non-zero integer (i.e. Z ∩ (P, Q) ̸= {0}). Here (P, Q) is the smallest ideal of Z[x] containing P and Q, (P, Q) := {αP + βQ|α, β ∈ Z[x]}. (iii) For which primes p and which integers n ≥ 1 is the polynomial xn − p...
Fact: If d > 2 is an integer, then there exists a prime q such that q divides d. (1) Let e and f be positive integers. Prove that if ged(e, f) = 1, then god(e?,f) = 1. (2) Let m be a positive integer. Prove that if m is rational, then m is an integer.
(11) Let A-{2" . 3", | n and m are non-zero integers). Show that 1 єА. (11) Let A-{2" . 3", | n and m are non-zero integers). Show that 1 єА.
1. Let n,m e N with n > 0. Prove that there exist unique non-negative integers a, ..., an with a: < 0+1 for all 1 Si<n such that m- Hint:(Show existence and uniqueness of a s.t. () <m<("), and use induction)
Problem 2 (Chinese Remaindering Theorem) [20 marks/ Let m and n be two relatively prime integers. Let s,t E Z be such that sm+tn The Chinese Remaindering Theorem states that for every a, b E Z there exists c E Z such that r a mod m (Va E Z) b mod nmod mn (3) where a convenient c is given by 1. Prove that the above c satisfies both ca mod m and cb mod n 2. LetxEZ. Prove...
Let p and n be integers. Prove that, if p is prime, then gcd(p, n) = p or gcd(p, n) = 1. . . (i.) Using proof by contrapositive (ii.) Using proof by contradiction