Let's say these are my current premises and goals:
IHl' : forall l' : list A, In a l'' \/ In a l' -> In a (l'' ++ l')
l' : list A
============================
....
Now, I want the hypothesis to get transformed like this:
IHl' : In a l'' \/ In a l' -> In a (l'' ++ l')
l' : list A
============================
....
So, basically I instantiate IHl'
with l'
. Is there any tactic which does this ? Rewriting or even introducing a new specialized hypothesis should do.