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Theorem nic-dfim 1434
Description: Define implication in terms of 'nand'. Analogous to ((φ (ψ ψ)) ↔ (φψ)). In a pure (standalone) treatment of Nicod's axiom, this theorem would be changed to a definition ($a statement). (Contributed by NM, 11-Dec-2008.) (Proof modification is discouraged.) (New usage is discouraged.)
Ref Expression
nic-dfim (((φ (ψ ψ)) (φψ)) (((φ (ψ ψ)) (φ (ψ ψ))) ((φψ) (φψ))))

Proof of Theorem nic-dfim
StepHypRef Expression
1 nanim 1292 . . 3 ((φψ) ↔ (φ (ψ ψ)))
21bicomi 193 . 2 ((φ (ψ ψ)) ↔ (φψ))
3 nanbi 1294 . 2 (((φ (ψ ψ)) ↔ (φψ)) ↔ (((φ (ψ ψ)) (φψ)) (((φ (ψ ψ)) (φ (ψ ψ))) ((φψ) (φψ)))))
42, 3mpbi 199 1 (((φ (ψ ψ)) (φψ)) (((φ (ψ ψ)) (φ (ψ ψ))) ((φψ) (φψ))))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 176   wnan 1287
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-nan 1288
This theorem is referenced by:  nic-stdmp  1455  nic-luk1  1456  nic-luk2  1457  nic-luk3  1458
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