EXISTS_NOT_CONV : conv
STRUCTURE
Conv
SYNOPSIS
Moves an existential quantification inwards through a negation.
DESCRIPTION
When applied to a term of the form ?x.~P, the conversion EXISTS_NOT_CONV returns the theorem: 
   |- (?x.~P) = ~(!x. P)

FAILURE
Fails if applied to a term not of the form ?x.~P.
SEEALSO
FORALL_NOT_CONV, NOT_EXISTS_CONV, NOT_FORALL_CONV
HOL  Kananaskis-14