Existential quantification of negation is equivalent to negation of universal quantification. Dual of alnex. See also the dual pair [df-ex] / alex. Theorem 19.14 of [Margaris] p. 90. (Contributed by NM, 12-Mar-1993.)
Existential quantification of negation is equivalent to negation of universal quantification. Dual of alnex. See also the dual pair [df-ex] / alex. Theorem 19.14 of [Margaris] p. 90. (Contributed by NM, 12-Mar-1993.)