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Theorem nic-dfim 1235
Description: Define implication in terms of 'nand'. Analogous to ((ph -/\ (ps -/\ ps)) <-> (ph -> ps)). In a pure (standalone) treatment of Nicod's axiom, this theorem would be changed to a definition ($a statement).
Assertion
Ref Expression
nic-dfim |- (((ph -/\ (ps -/\ ps)) -/\ (ph -> ps)) -/\ (((ph -/\ (ps -/\ ps)) -/\ (ph -/\ (ps -/\ ps))) -/\ ((ph -> ps) -/\ (ph -> ps))))

Proof of Theorem nic-dfim
StepHypRef Expression
1 nic-justim 1232 . . 3 |- ((ph -> ps) <-> (ph -/\ (ps -/\ ps)))
21bicomi 189 . 2 |- ((ph -/\ (ps -/\ ps)) <-> (ph -> ps))
3 nic-justbi 1234 . 2 |- (((ph -/\ (ps -/\ ps)) <-> (ph -> ps)) <-> (((ph -/\ (ps -/\ ps)) -/\ (ph -> ps)) -/\ (((ph -/\ (ps -/\ ps)) -/\ (ph -/\ (ps -/\ ps))) -/\ ((ph -> ps) -/\ (ph -> ps)))))
42, 3mpbi 206 1 |- (((ph -/\ (ps -/\ ps)) -/\ (ph -> ps)) -/\ (((ph -/\ (ps -/\ ps)) -/\ (ph -/\ (ps -/\ ps))) -/\ ((ph -> ps) -/\ (ph -> ps))))
Colors of variables: wff set class
Syntax hints:   -> wi 3   <-> wb 163   -/\ wnand 1229
This theorem is referenced by:  nic-stdmp 1256  nic-luk1 1257  nic-luk2 1258  nic-luk3 1259
This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7
This theorem depends on definitions:  df-bi 164  df-or 241  df-an 242  df-nand 1230
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