strip_pexists : term -> term list * term
STRUCTURE
LIBRARY
pair
SYNOPSIS
Iteratively breaks apart paired existential quantifications.
DESCRIPTION
strip_pexists "?p1 ... pn. t" returns ([p1,...,pn],t). Note that
   strip_pexists(list_mk_pexists([[p1,...,pn],t))
will not return ([p1,...,pn],t) if t is a paired existential quantification.
FAILURE
Never fails.
SEEALSO
HOL  Kananaskis-13