Thread: Injective Compositition
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Apr10-12, 11:06 AM   #3
 
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Quote by dijkarte View Post
We need to show that g(f(a)) = g(f(b)) ==> a = b holds true for all a, b in A.
No, you don't need to show that, that's given.

You need to show that f is an injection. That is: f(a)=f(b) ==> a=b. That is what you need to show.