Originally Posted by

**DukeSteve** Hello Experts,

Here is the question, and what I did:

Q: Given a ring with division D char(D) != 2, F = Centralizer of D (means that F becomes a field). Given that x in D isn't in F but x^2 is included in F.

Needed to prove that there exists y in D and y*x*y^(-1) = -x

and also that y^2 is in C_D({x}) where C_D is the centralizer of the set {x} sub set of D.

What I did is:

I know that x is not in F so there exists such s in D that sx!=xs

Let's call sx-xs = y there is y^-1 because every non zero element in D is invertible.

Then I just tried to plug it in the equation: (sx-xs)*x*(sx-xs)^(-1) =>

(sx-xs)^(-1) should be 1/(sx-xs) but it gives nothing.

Please tell me how to solve it....I know that I miss something, please guide me step by step.