P_PSKOLEM_CONV
PairRules.P_PSKOLEM_CONV : (term -> conv)
Introduces a user-supplied Skolem function.
P_PSKOLEM_CONV takes two arguments. The first is a variable f, which
must range over functions of the appropriate type, and the second is a
term of the form !p1...pn. ?q. t (where pi and q may be pairs).
Given these arguments, P_PSKOLEM_CONV returns the theorem:
|- (!p1...pn. ?q. t) = (?f. !p1...pn. tm[f p1 ... pn/q])
which expresses the fact that a skolem function f of the universally
quantified variables p1...pn may be introduced in place of the the
existentially quantified pair p.
Failure
P_PSKOLEM_CONV f tm fails if f is not a variable, or if the input
term tm is not a term of the form !p1...pn. ?q. t, or if the
variable f is free in tm, or if the type of f does not match its
intended use as an n-place curried function from the pairs p1...pn
to a value having the same type as p.