From: Victor Porton <porton@narod.ru>
I have the following problem (I may attempt to solve it myself but I think
that would lead to a messy non-optimal solution, but I want to see the best
way to solve it):
How to prove that a given function is injection?
theory test
imports Main_ZF
begin
theorem assumes "f: A->B" and "w:A & x:A ==> (fw=f
x --> w=x)"
shows "f: inj(A,B)"
sorry
end
\--
Victor Porton - http://portonvictor.org
Last updated: Nov 21 2024 at 12:39 UTC