== Validade global de sequentes ==
=== <math> (\exists x )(\forall y. ) \varphi </math> ▷ <math> (\forall y )(\exists x. ) \varphi </math> ===
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=== <math> (\forall y )(\exists x. ) \varphi </math> ▶ <math> (\exists x )(\forall y. ) \varphi </math> ===
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