Specializes a theorem, with type instantiation if necessary.
DESCRIPTION
This rule specializes a paired quantification as does PSPEC;
it differs from it in also instantiating the type if needed:
A |- !p:ty.tm
----------------------- IPSPEC "q:ty'"
A |- tm[q/p]
(where q is free for p in tm, and ty' is an instance
of ty).
FAILURE
IPSPEC fails if the input theorem is not universally quantified, if
the type of the given term is not an instance of the type of the
quantified variable, or if the type variable is free in the
assumptions.