# Group Proofs : Properties of Groups

Not what you're looking for?

Let G be a group. x and y are elements of G. Prove that:

a. The inverse of xy is y^-1x^-1

b. The identity element, e, is unique

c. The inverse of any element x of G is unique

d. If xy = xz then y = z

e. If x^-1y^-1=y^-1x^-1 then xy = yx

f. If every element x of G satisfies x x = e, then for any two elements, x, y, of G, we have xy = yx

Note that e is an element of G such that ex = x

Also note that for all the above, the group operation is not necessarily multiplication.

##### Purchase this Solution

##### Solution Summary

Group properties are invesigated.

##### Solution Preview

Proof:

a. Since (xy)*(y^-1x^-1)=x*(y*y^-1)*x^-1=x*e*x^-1=1. Thus the inverse of xy is y^-1x^-1.

b. Suppose we have two indentiies e and e'. Then we have e*e'=e and e*e'=e'. This implies that e=e'. So the identity e of G is ...

##### Purchase this Solution

##### Free BrainMass Quizzes

##### Exponential Expressions

In this quiz, you will have a chance to practice basic terminology of exponential expressions and how to evaluate them.

##### Multiplying Complex Numbers

This is a short quiz to check your understanding of multiplication of complex numbers in rectangular form.

##### Solving quadratic inequalities

This quiz test you on how well you are familiar with solving quadratic inequalities.

##### Graphs and Functions

This quiz helps you easily identify a function and test your understanding of ranges, domains , function inverses and transformations.

##### Probability Quiz

Some questions on probability