
1. Let G = {a, b, c, d, e} be a set with an associative binary operation multiplication such that ab = ba = d, ed = de = c. Prove that G under this multiplication cannot consist of a group. Hint: Assume that G under this operation does consist of a group. Try to complete the multiplication table and deduce a contradiction. 2. Let G be a group containing 4 elements a, b, c, and d. Under the group...
1. Show that the set of rational numbers of the form m /n, where m, n E Z and n is odd is a subgroup of QQ under addition. 2. Let H, K be subgroups of a group G. Prove: H n K is a subgroup of G 3. Let G be an abelian group. Let S-aEG o(a) is finite . Show that S is a subgroup of G 4. What is the largest order of a permutation in S10?...
a b 5. Let G= { |a E U5, b e Z5}. G is an Abelian group under matrix multiplication (modulo 5). Prove the following: :) a (a) What is G] =? (b) Express G as a direct sum of cyclic groups.
Always give rigorous arguments I. (A) Let G be a group under * and let g E G with o(g) = n (finite) (i) Show that g can never go back to any previous positive power of g* (1k< n) when taking up to the nth power (cf. g), e., that there are no integers k and m such that 1< k<m<n and such that g*-gm (ii) How many elements of the set (e, g,g2.... .g"-) are actually distinct? (iii)...
ei0 : 0 E R} be the group of all complex numbers on the unit circle under multiplication. Let ø : R -> U 1. (30) Let R be the group of real numbers under addition, and let U be the map given by e2Tir (r) (i) Prove that d is a homomorphism of groups (ii) Find the kernel of ø. (Don't just write down the definition. You need to describe explicit subset of R.) an real number r for...
2. Consider the relation E on Z defined by E n, m) n+ m is even} equivalence relation (a) Prove that E is an (b) Let n E Z. Find [n]. equivalence relation in [N, the equivalence class of 3. We defined a relation on sets A B. Prove that this relation is an (In this view, countable sets the natural numbers under this equivalence relation). exactly those that are are
2. Consider the relation E on Z defined by...
QUESTION 8 Let G is an abelian group with the additive operation. Define the operation of multiplication by the rule ab- a- b for all a,b of G. Is G a ring?
QUESTION 8 Let G is an abelian group with the additive operation. Define the operation of multiplication by the rule ab- a- b for all a,b of G. Is G a ring?
Question 4
Exercise 1. Let G be a group such that |G| is even. Show that there exists an EG,17e with x = e. Exercise 2. Let G be a group and H a subgroup of G. Define a set K by K = {z € G war- € H for all a € H}. Show that (i) K <G (ii) H <K Exercise 3. Let S be the set R\ {0,1}. Define functions from S to S by e(z)...