Question

In each of the following, prove that the specified subset H is not a subgroup of...

In each of the following, prove that the specified subset H is not a subgroup of the given group G: (a) G = (Z, +), H is the set of positive and negative odd integers, along with 0. (b) G = (R, +), H is the set of real numbers whose square is a rational number. (c) G = (Dn, ◦), H is the set of all reflections in G.

Homework Answers

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
In each of the following, prove that the specified subset H is a subgroup of the...
In each of the following, prove that the specified subset H is a subgroup of the given group G. Note: in each case, you may assume that the given operation is associative. (a) G = (C ∗ , ·), H is the set of complex numbers of norm 1; i.e., the unit circle in the complex plane. (b) G = (Q, +), for fixed n, H is the set of rational numbers whose denominators divide n. (c) G = (Dn,...
Prove that if H,K are two subsets in group G with H is the subset of...
Prove that if H,K are two subsets in group G with H is the subset of K, then CG(K)(the centralizer of K in G) is a subgroup of CG(H)
Prove the following using the specified technique: (a) Prove by contrapositive that for any two real...
Prove the following using the specified technique: (a) Prove by contrapositive that for any two real numbers,x and y,if x is rational and y is irrational then x+y is also irrational. (b) Prove by contradiction that for any positive two real numbers,x and y,if x·y≥100 then either x≥10 or y≥10. Please write nicely or type.
In each part below, a group G and a subgroup H are given. Determine whether H...
In each part below, a group G and a subgroup H are given. Determine whether H is normal in G. If it is, list the elements of the quotient group G/H. (a) G = Z-15 × Z-20 and H = <(10, 17)> (b) G = S-6 and H = A-6 (c) G = S-5 and H = A-4
Let H be a subgroup of a group G. Let ∼H and ρH be the equivalence...
Let H be a subgroup of a group G. Let ∼H and ρH be the equivalence relation in G introduced in class given by x∼H y⇐⇒x−1y∈H, xρHy⇐⇒xy−1 ∈H. The equivalence classes are the left and the right cosets of H in G, respectively. Prove that the functionφ: G/∼H →G/ρH given by φ(xH) = Hx−1 is well-defined and bijective. This proves that the number of left and right cosets are equal.
Let G be a group with subgroups H and K. (a) Prove that H ∩ K...
Let G be a group with subgroups H and K. (a) Prove that H ∩ K must be a subgroup of G. (b) Give an example to show that H ∪ K is not necessarily a subgroup of G. Note: Your answer to part (a) should be a general proof that the set H ∩ K is closed under the operation of G, includes the identity element of G, and contains the inverse in G of each of its elements,...
Using field axioms and order axioms prove the following theorems (i) The sets R (real numbers),...
Using field axioms and order axioms prove the following theorems (i) The sets R (real numbers), P (positive numbers) and [1, infinity) are all inductive (ii) N (set of natural numbers) is inductive. In particular, 1 is a natural number (iii) If n is a natural number, then n >= 1 (iv) (The induction principle). If M is a subset of N (set of natural numbers) then M = N The following definitions are given: A subset S of R...
In the following determine whether the systems described are groups. If they are not, point out...
In the following determine whether the systems described are groups. If they are not, point out which of the group axioms fail to hold. (a) G = set of all integers, a· b = a - b. (b) G = set of all positive integers, a · b = ab, the usual product of integers. (c) G = a0 , a 1 , ... , a6 where ai · a i = ai + i if i + j <...
For a given real number x , there is a natural number n which is larger...
For a given real number x , there is a natural number n which is larger than x . True False The supremum of the set of negative integers is 0. True False The supremum of a bounded set of rational numbers is rational. True False The supremum of a bounded set of irrational numbers is irrational. True False Every rational number is the supremum of a bounded set of irrational numbers. True False Every bounded sequence is a Cauchy...
Using field and order axioms prove the following theorems: (i) Let x, y, and z be...
Using field and order axioms prove the following theorems: (i) Let x, y, and z be elements of R, the a. If 0 < x, and y < z, then xy < xz b. If x < 0 and y < z, then xz < xy (ii) If x, y are elements of R and 0 < x < y, then 0 < y ^ -1 < x ^ -1 (iii) If x,y are elements of R and x <...