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Axiom ax-6 953
Description: Axiom of Quantified Negation. This axiom is used to manipulate negated quantifiers. One of the 4 axioms of pure predicate calculus. Equivalent to axiom scheme C7' in [Megill] p. 448 (p. 16 of the preprint). Another equivalent variant ax6-2 1001 appears as Axiom C5-2 of [Monk2] p. 113. An alternate axiomatization could use ax467 997 in place of ax-4 951, ax-6 953, and ax-7 954.
Assertion
Ref Expression
ax-6 |- (-. A.x -. A.xph -> ph)

Detailed syntax breakdown of Axiom ax-6
StepHypRef Expression
1 wph . . . . . 6 wff ph
2 vx . . . . . 6 set x
31, 2wal 950 . . . . 5 wff A.xph
43wn 2 . . . 4 wff -. A.xph
54, 2wal 950 . . 3 wff A.x -. A.xph
65wn 2 . 2 wff -. A.x -. A.xph
76, 1wi 3 1 wff (-. A.x -. A.xph -> ph)
Colors of variables: wff set class
This axiom is referenced by:  a6e 966  hbnt 978  ax46 991  ax67 994  ax467 997  modal-b 1004  equid 1113
Copyright terms: Public domain