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Group Theory

Groups, Order and Commutativity

1. If x is an element of a group and x is of order n then the elements 1, x, x^2,...x^n-1 are distinct (don't know how to show this!) 2. Let Y=<u,v/u^4=v^3=1, uv=v^2u^2> Y here is a group show a) v^2=v^-1 b) v commutes with u^3 c) v commutes with u d)uv=1 e)u=1, deduce that v=1 and conclude that Y=1

Dihedral Groups

Use the gemerators and relations for D(sub2n)=<r,s/r^n=s^2=1,rs=sr^-1> to show that if x is any element of D2n, that is not a power of r, then rx=xr^-1. Here D2n is the dihedral group of order 2n

Groups and Distinct Elements

Let G be a group and let be two distinct elements. Let n be the order of g and m be the order of h. Prove or disprove that there is no pair i,j , such that . Please see the attached file for the fully formatted problems.

Continuous Maps, Homomorphisms and Cyclic Groups

Let f: S^n --> S^n be a continuous map. Consider the induced homomorphism f*: H~_n (S^n) --> H~_n (S^n), where H~_n is a reduced homology group. Then from the fact that H~_n (S^n) is an infinite cyclic group, it follows that there is a unique integer d such that f*(u) = du for any u in H~_n (S^n). How exactly does "ther

Nilpotent Groups

Let G = UT (n,F) be the set of the upper triangular n x n matrices with entries in a field F with p elements and 1's on the diagonal. The operation in G is matrix multiplication. (a) Show that G is a group (b) Show that G is a finite p-group (c) Consider the upper central series of G: 1 = Z_0 (G) <= Z_1 (G) <= Z_2 (G) <

Group of order 9

This is the question: Consider small groups. (i) Show that a group of order 9 is isomorphic to Z9 or Z3 x Z3 (ii) List all groups of order at most 10 (up to isomorphism)

Symmetric groups

Symmetric groups: G = Sn. (i) Let g1, g2 belong G be two disjoint cycles, and let g = g1g2. Prove that o(g) = lcm { o( g1), o(g2)}, where lcm stands for the least common multiple. (ii) Let g= g1g2 ... gr belong G, where g1,g2, ... gr are disjoint cycles. Prove that o(g) = lcm {o(g1), o(g2), ... o(gr)}. Can you

Path-connected Space : Abelian Group

Let x0 and x1 be points of the path-connected space X. Show that Pi_1(X,x0) is abelian iff for every pair a and b of paths from x0 to x1, we have a'=b', where a'([f])=[a-]*[f]*[a];( a- means the reverse of a.) and [f] belongs to Pi_1(X,x0). a':Pi_1(X,x0)->Pi_1(X,x1).

Group Structure, Order of two groups

I have questions about constructing a group structure, how to identify the order of a paired group when they have different orders and method of figuring out the group identity and the inverse of a pair that contained in the paired group. --- If G and H are groups then explain how to equip G x H with a group structure. If G

Formation of a Group under an Associative Product

Question: Let G be a nonempty set closed under an associative product, which in addition satisfies: (a) There exists an e in G such that e.a = a for all a in G. (b) Given a in G, there exists an element y(a) in G such that y(a).a = e. Then G is a group under this product.

Group Theory - Group of Even Order

Modern Algebra Group Theory (XXII) Group of Even Order If G is a group of even order, prove it has an element a which is not equal to e satisfying a^2 = e. The fully formatted problem is in the attached file.