two questions,please! 11. Let φ: R → S be a ring hornomorphism. Prove that if R is a field and φ(R)メ(0), then φ(R) is a field 12, Give an example where φ: R → s is a surjective homomorphisms of u...
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....
11. (a) Let F be a field. Prove FixF Rİr (b) Let R be a commutative ring with identity. Prove that one can have R. 11. (a) Let F be a field. Prove FixF Rİr (b) Let R be a commutative ring with identity. Prove that one can have R.
Please solve from a) to e), thank you. 1. Let R be a com ive ring of charact a) Prove that (x+y)P-y. [3] b) Deduce that the map фр: R R, фр(x)-x", is a ring homomorphism. [1] c) Compute Op in the case R is the ring Zp. [2] d) Prove that φp is injective if R has no zero-divisors. [2] e) Give an example of a commutative ring of characteristic p such that фр is not surjective. [3]
18. Let o: R+ S be a ring homomorphism. Prove each of the following statements. (a) If R is a commutative ring, then (R) is a commutative ring. (b) (0)=0. (c) Let 18 and 1s be the identities for R and S, respectively. If o is onto, then (1r) = 1s. (d) If R is a field and $(R) +0, then (R) is a field.
6. Let R be a ring, and let 11 and 12 be ideals of R. We define the product of 11 and 12 to be 1112 = {TER:r => aibi, with k > 1, Q1, ..., ak € 11, b1,..., bk € 12 In other words, an element of the product 1.12 is a finite sum of products a;bi, where a, comes from I and bi comes from 12. (a) Prove that 11 12 is an ideal of R, contained...
= Let R be a ring (not necessarily commutative) and let I be a two-sided ideal in R. Let 0 : R + R/I denote the natural projection homomorphism, and write ř = º(r) = r +I. (a) Show that the function Ø : Mn(R) + Mn(R/I) M = (mij) Ø(M)= M is a surjective ring homomorphism with ker ý = Mn(I). (b) Use Homework 11, Problem 2, to argue that M2(2Z) is a maximal ideal in M2(Z). (c) Show...
How to prove these two questions? 3. Let f : 10, 11 → [O, 1] be continuous. Then there exists x [0,1] such that f(x)-x. 4. A function f : R → R is continuous if and only if the pre-image of all open sets are open. Note: The pre-image of a set s is defined as f-1 (S)-{re R : f(x) є S). For example if f(x), then f ((0,1) (1,0)U (0, 1). =x- 1,0) U (0, 1
Question 8 (Chapters 6-7) 12+2+2+3+2+4+4-19 marks] Let 0メS C Rn and fix E S. For a E R consider the following optimization problem: (Pa) min a r, and define the set K(S,x*) := {a E Rn : x. is a solution of (PJ) (a) Prove that K(S,'). Hint: Check 0 (b) Prove that K(S, r*) is a cone. (c) Prove that K(S,) is convex d) Let S C S2 and fix eS. Prove that K(S2, ) cK(S, (e) Ifx. E...
Question 7 (Chapters 6-7) 2+2+2+3+2+4+4-19 mark Let 0メs c Rn and fix r' E S. For a R" consider the following optimization problem: (Pa) min ar res and define the set K(S,) (aER z" is a solution of (Pa)) (e) If z' e int(S), prove that K(S, (0) (1) If possible, find a set S CR" and s* E S such that K(S,) (g) Let SB, 0.1] (rR l2l3 1) (the closed (, unit ball) and consider (1,0)7. Prove that...