I have two equal subgoals like this:
prove_me (x::xs) = true
prove_me (x::xs) = true
Proofs will be equals. How I can solve the second goal using the first one?
You cannot literally reuse the proof of one goal on another goal, but you can prove an auxiliary lemma:
assert (H : prove_me (x::xs) = true).
{ (* proof of result *) }
Then, you can use H
to discharge the two subgoals once they show up.