Thread: prove

Assume that alpha:S-T, and beta: T-U, gamma: T-U. prove each of the following statements

A) If alpha and beta are invertible, then beta of alpha is invertible.

Originally Posted by mandy123

Assume that alpha:S-T, and beta: T-U, gamma: T-U. prove each of the following statements

A) If alpha and beta are invertible, then beta of alpha is invertible.

I do the first one.
A function is invertible if and only if it is one-to-one.
Say .
Thus, is invertible.