`intros` non-predicate patterns

[Jan Tusil]

Currently, intros H check whether the LHS is a predicate pattern. I believe there is no need for it - the deduction theorem works even for non-predicate patterns. Therefore I would like to relax that restriction.

[Xiaohong Chen]

This is the deduction theorem:
Gamma U {psi} |- phi iff Gamma |- \floor{psi} -> phi
where psi has no free variables.
If psi is a predicate pattern then \floor{psi} = psi, so we have
Gamma U {psi} |- phi iff Gamma |- psi -> phi
which is the most common form we use in practice (from right to left).

[Jan Tusil]

Oh, I see, I didn't notice the \floor. Thanks.