----------------------------------------------------------------------
NOT_FORALL_CONV                                                 (Conv)
----------------------------------------------------------------------
NOT_FORALL_CONV : conv

SYNOPSIS
Moves negation inwards through a universal quantification.

KEYWORDS
conversion, quantifier, universal, negation.

DESCRIBE
When applied to a term of the form {~(!x.P)}, the conversion
{NOT_FORALL_CONV} returns the theorem:

   |- ~(!x.P) = ?x.~P

It is irrelevant whether {x} occurs free in {P}.

FAILURE
Fails if applied to a term not of the form {~(!x.P)}.

SEEALSO
Conv.EXISTS_NOT_CONV, Conv.FORALL_NOT_CONV, Conv.NOT_EXISTS_CONV.

----------------------------------------------------------------------