5. Let Zli_ {a + bi l a,b E Z. i2--1} be the Gaussian integers. Define a function for all a bi E Zi]. We call N the norm (a) Prove that N is multiplicative. This is, prove that for all a bi, c+di E Z...
Let R denote the ring of Gaussian integers, i.e., the set of all complex numbers a + bi with a, b ∈ Z. Define N : R → Z by N(a + bi) = a^2 + b^2. (i) For x,y ∈ R, prove that N(xy) = N(x)N(y). (ii) Use part (i) to prove that 1, −1, i, −i are the only units in R.
16. (8 points) Let Z be the integers and let A - Zx Z. Define the relation R on A by (a, b) R(c, d) if and only if a c and b 3 d for all (a, b), (c, d)E A. Prove that R is a partial ordering on A that is not a total ordering. 16. (8 points) Let Z be the integers and let A - Zx Z. Define the relation R on A by (a, b)...
Let R be an ED but not a field, with a norm function N R-Z U0 such that N(ab for all a, bE R. (a) Prove that N(1R) (b) If r E R is a unit, show that N(r) 1. (c) If r E R is nonzero, show that N(r) 0. (d) For any r E R, prove that if N(r) 1, then r is a unit N(a)N(b) e) For any r e R if N() is a prime mumber,...
5.7. Let n an E C be a multiplicative function defined by a 1 and ifn-2, pθ and 0 < θ < 1 . Prove that, as x → oo, we have where lEpl ano(a) for some constant r. 5.7. Let n an E C be a multiplicative function defined by a 1 and ifn-2, pθ and 0
2 (1) For z E C, define exp z - n-0 (a) Prove that the infinite series converges absolutely for z E C (b) Prove that when z є R, the definition of exp z given above is consistent with the one given in problem (2a), assignment 16. Definition from Problem (2a): L(x(1/t)dt E(z) = L-1 (z) 2 (1) For z E C, define exp z - n-0 (a) Prove that the infinite series converges absolutely for z E C...
Theorem 16.1. Let p be a prime number. Suppose r is a Gaussian integer satisfying N(r) = p. Then r is irreducible in Z[i]. In particular, if a and b are integers such that a² +62 = p, then the Gaussian integers Ea – bi and £b£ai are irreducible. Exercise 16.1. Prove Theorem 16.1. (Hint: For the first part, suppose st is a factorization of r. You must show that this factorization is trivial. Apply the norm to obtain p=...
Let A e Cpxp,A e C, and let 11-11 a multiplicative norm on Cpxp. Use Theorem 7.27 of your lecture notes to show that if Al > ll All , then 1. XIp A is invertible and Ip Theorem 7.27. If Il is a sub-multiplicative norm on C, then pl 1. Moreover, i X E CPXP and |X|l < 1, then 1. Ip X is invertible. 2. (1,-X)-1-).X' ; i.e., the sum converges j-0 SI Let A e Cpxp,A e...
Problem 11.16. Let X = {XE Ζ+ : x-100): that is, X is the set of all integers from l to 100. For each Y E 9(X) we define AY (2 E 9(X) : Y and Z have the same number of elements) (a) Prove that AY : Y є 9(X)} partitions 9(X). (b) Letdenote the equivalence relation on (X) that is associated with this partition (according to Theorem 11.4). If possible, find A, B, and C such that 1....
4. (a) For n eZ, define multiplication mod n by ao b-a b (where indicates regular real number multiplication), prove that On is a binary operation on Zn. That is, (Hint your proof will be very similar to the proof for homework 4 problem 7ab) (b) Let n E Z. Is the binary algebraic structure 〈L,On) always a group? Explain. (c) Prove There exists be Zn such that a n I if and only if (a, n)1. (d) It is...
Advanced Calculus (3) Let the function f(x) 0 if x Z, but for n e z we have f(n) . Prove that for any interval [a3] the function f is integrable and Ja far-б. Hint: let k be the number of integers in the interval. You can either induct on k or prove integrability directly from the definition or the box-sum criterion. (3) Let the function f(x) 0 if x Z, but for n e z we have f(n) ....