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I. Functions and Isomorphisms. Let G be a group and let a EG be any non-identity...
Let a : G + H be a homomorphism. Which of the following statements must necessarily be true? Check ALL answers that are necessarily true. There may be more than one correct answer. A. If kera is trivial (i.e., ker a = {eg}), then a is injective. B. If the image of a equals H, then a is injective. C. The first isomorphism theorem gives an isomorphism between the image of a and a certain quotient group. D. The first...
(6) The center of a group G is the set ZG) = {x EG: zg = gx for all g € G}. Thus, x E Z(G) if x commutes with element of G. Prove that Z(G) is a subgroup of G. (7) An automorphism of a group G is an isomorphism from G to G. Let G be a group and let x E G. Prove that the function 4x: G + G defined by 4x(g) = xgx for all...
1- (2,5+2,5 mark) Consider in GL(2, Q), the subset (a=1 or a=-1),bez Prove that H, with multiplication, is a subgroup of GL(2,Q) a) Is the function b) an homomorphism of groups? Justify your answer 2 (3 marks) Let G be a group and a E G an element of order 12. Find the orders of each of the elements of (a) 3- (1+1,5 marks) Let G be a group such that any non-identity element has order 2. Prove that a)...
2. Let f : A ! B. DeÖne a relation R on A by xRy i§ f (x) = f (y). a. Prove that R is an equivalence relation on A. b. Let Ex = fy 2 A : xRyg be the equivalence class of x 2 A. DeÖne E = fEx : x 2 Ag to be the collection of all equivalence classes. Prove that the function g : A ! E deÖned by g (x) = Ex is...
4. Recall that an element e in any group G is called an identity element if for every g € G, eg = g = ge. (a) Give a counterexample to prove that o is not an identity element in Sx. (b) Give a counterexample to prove that is not an identity element in Sx. (c) Give a counterexample to prove that is not an identity element in Sx. (a) Give a counterexample to prove that p is not an...
5. Let A = P(R). Define f : R → A by the formula f(x) = {y E RIy2 < x). (a) Find f(2). (b) Is f injective, surjective, both (bijective), or neither? Z given by f(u)n+l, ifn is even n - 3, if n is odd 6. Consider the function f : Z → Z given by f(n) = (a) Is f injective? Prove your answer. (b) Is f surjective? Prove your answer
Let f : A rightarrow D and g : B rightarrow C be functions. For each part, if the answer is yes, then prove it, otherwise give a counterexample. Suppose f is one-to-one (injective) and g is onto (surjective). Is go f one-to-one (injective)? Suppose f is one-to-one (injective) and g is onto (surjective). Is g f onto (surjective)? Suppose g is one-to one. Is g one-to-one? Suppose g f onto. Is g onto?
Let S ⊂ R be a non-empty set. For any functions f and g from S into R, define d(f,g) := sup{|f(x)−g(x)| : x∈S}. Is d always a metric on the set F of functions from S into R? Why or why not? What does your answer suggest that we do to find a (useful) subset of functions from S to R on which d is a metric, if F does not work? Give a brief justification for your fix.
Prove If the functions are injective, surjective, or bijective. You must prove your answer. For example, if you decide a function is only injective, you must prove that it is injective and prove that it is not surjective and that it is not bijective. Similarly, if you claim a function is only surjective, you must prove it is surjective and then prove it is not injective and not bijective. - Define the function g: N>0 → N>0 U {0} such that g(x) = floor(x/2). You may use the fact that...
3 Let p and q be prime numbers and let G be a non-cyclic group of order pq. Let H be a subgroup of G.Show that either H is cyclic or H-G. 12 - Let I and J, be ideals in R. In, the homomorphismJ f: (!+J a → a+J use the First Isomorphism Theorem to prove that I+J