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PEXISTS_NOT_CONV                                           (PairRules)
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PEXISTS_NOT_CONV : conv

KEYWORDS
conversion, quantifier, existential, negation.

LIBRARY
pair

SYNOPSIS
Moves a paired existential quantification inwards through a negation.

DESCRIBE
When applied to a term of the form {?p. ~t}, the conversion {PEXISTS_NOT_CONV}
returns the theorem:

   |- (?p. ~t) = ~(!p. t)




FAILURE
Fails if applied to a term not of the form {?p. ~t}.

SEEALSO
Conv.EXISTS_NOT_CONV, PairRules.PFORALL_NOT_CONV,
PairRules.NOT_PEXISTS_CONV, PairRules.NOT_PFORALL_CONV.

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