LEFT_IMP_PEXISTS_CONV : conv
STRUCTURE
PairRules
SYNOPSIS
Moves a paired existential quantification of the antecedent outwards through an implication.
DESCRIPTION
When applied to a term of the form (?p. t) ==> u, the conversion LEFT_IMP_PEXISTS_CONV returns the theorem: 
   |- (?p. t) ==> u = (!p'. t[p'/p] ==> u)
where p' is a primed variant of the pair p that does not contain any variables that appear free in the input term.
FAILURE
Fails if applied to a term not of the form (?p. t) ==> u.
SEEALSO
LEFT_IMP_EXISTS_CONV, PFORALL_IMP_CONV, RIGHT_IMP_PFORALL_CONV
HOL  Kananaskis-13