- #1
dmatador
- 120
- 1
let G be a group following that whenever a, b and c belong to G and ab = ca, then b = c. prove that G is Abelian.
here is what i have for the proof:
(ab)c = c(ab)
let c = aba^-1 (trying to find a c which which allows for commutativity)
so (ab)aba^-1 = aba^-1(ab)
(ab)aba^-1 = ab(a^-1 a)b
then we see that aba^-1 = b (b = c)
a on both sides on the right: aba^-1 a = ba
then we can see that ab = ba which proves commutativity.
I am not capable of using Latex at the moment, so a^-1 means the inverse of a.
How is this? Where does b = c fit into all of this? I sort of came upon it through trying to prove commutativity and figured that that is logical. So I am not really all the comfortable with it, so I am looking for maybe some insight on how to better approach a problem like this. Thanks for any help.
here is what i have for the proof:
(ab)c = c(ab)
let c = aba^-1 (trying to find a c which which allows for commutativity)
so (ab)aba^-1 = aba^-1(ab)
(ab)aba^-1 = ab(a^-1 a)b
then we see that aba^-1 = b (b = c)
a on both sides on the right: aba^-1 a = ba
then we can see that ab = ba which proves commutativity.
I am not capable of using Latex at the moment, so a^-1 means the inverse of a.
How is this? Where does b = c fit into all of this? I sort of came upon it through trying to prove commutativity and figured that that is logical. So I am not really all the comfortable with it, so I am looking for maybe some insight on how to better approach a problem like this. Thanks for any help.