10. Prove that every nonzero element of Z, is either a unit or a zero divisor,...
Definition. Let g be in G and g 0 and g not a unit. If every divisor of g is either a unit or an associate of g, then g is prime in G; if g is not prime in G (thus g has a divisor different from g, ig, -g, or - ig), then g is composite. Exercise 1.73. The Gaussian integers can be partitioned into four noninter- secting classes: 0, the units, the primes, and the composites. Exercise...
for every nonzero element a n o (u)-' . Determine if the following statement is true or false, then either prove it or find a 0, then every counterexample: If A is a commutative ring with unity and char(A) nonzero element a E A has infinite order.
OD (2) Show that if m>gedlm,a)>l, then [a] is a zero-divisor' in 2/m2 An element [a] in 2/m2 is a zero-divisor if [a] * [O] and there is a [b]+[O] in 2/m2 such that [a][b]=[0]. (3) Which elements in Z/m2 have multiplicative inverses? Hint: If d=acdm.a), then abed (mod m), for some b€2
Let R be a commutative ring with no nonzero zero divisor and elements r1,r2,.. . ,Tn where n is a positive integer and n 2. In this problem you will sketch a proof that R is a field (a) We first show that R has a multiplicative identity. Sinee the additive identity of R is, there is a nonzero a E R. Consider the elements ari, ar2, ..., arn. These are distinct. To see O. Since R conelude that0, which...
Definition A: Let R be ring and r e R. Then r is called a zero-divisor in Rifr+0r and there exists SER with s # OR and rs = OR. Exercise 1. Let R be a ring with identity and f € R[2]. Prove or give a counter example: (a) If f is a zero-divisor in R[x], then lead(f) is a zero-divisor in R. (b) If lead(f) is a zero- divisor in R[x], then f is a zero-divisor in R[2]....
Number Theory
13 and 14 please!
13)) Let n E N, and let ā, x, y E Zn. Prove that if ā + x = ā + y, then x-y. 14. In this exercise, you will prove that the additive inverse of any element of Z, is unique. (In fact, this is true not only in Z, but in any ring, as we prove in the Appendix on the Student Companion Website.) Let n E N, and let aE Z...
It is important.I am waiting your help.
11. a) Prove that every field is a principal ideal domain. b) Show that the ring R nontrivial ideal of R. fa +bf2a, b e Z) is not a field by exhibiting a 12. Let fbe a homomorphism from the ring R into the ring R' and suppose that R ker for else R' contains has a subring F which is a field. Establish that either F a subring isomorphic to F 13....
T'he goal of this problem is to establish the following remarkable result: Bezout's theorern. If a, be Z50, then 3x, y є Z such that gcd(a, b) = ax + by. Here ged(a, b) denotes the greatest common divisor of a and b (i.e. the largest positive integer that divides both a and b). Throughout this problem, we'll use the notation (a) Write down five numbers that live in 2Z +3Z. What's a simpler name for the set 2Z +3Z?...
Please solve all questions
1. Let 0 : Z/9Z+Z/12Z be the map 6(x + 9Z) = 4.+ 12Z (a) Prove that o is a ring homomorphism. Note: You must first show that o is well-defined (b) Is o injective? explain (c) Is o surjective? explain 2. In Z, let I = (3) and J = (18). Show that the group I/J is isomorphic to the group Z6 but that the ring I/J is not ring-isomorphic to the ring Z6. 3....
please answer questions #7-13
7. Use a direct proof to show every odd integer is the difference of two squares. [Hint: Find the difference of squares ofk+1 and k where k is a positive integer. Prove or disprove that the products of two irrational numbers is irrational. Use proof by contraposition to show that ifx ty 22 where x and y are real numbers then x 21ory 21 8. 9. 10. Prove that if n is an integer and 3n...