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Theorem rnlem 579
Description: Lemma used in construction of real numbers.
Assertion
Ref Expression
rnlem (((φψ) ∧ (χθ)) ↔ (((φχ) ∧ (ψθ)) ∧ ((φθ) ∧ (ψχ))))

Proof of Theorem rnlem
StepHypRef Expression
1 anandir 393 . 2 (((φψ) ∧ (χθ)) ↔ ((φ ∧ (χθ)) ∧ (ψ ∧ (χθ))))
2 anandi 392 . . 3 ((φ ∧ (χθ)) ↔ ((φχ) ∧ (φθ)))
3 anandi 392 . . 3 ((ψ ∧ (χθ)) ↔ ((ψχ) ∧ (ψθ)))
42, 3anbi12i 369 . 2 (((φ ∧ (χθ)) ∧ (ψ ∧ (χθ))) ↔ (((φχ) ∧ (φθ)) ∧ ((ψχ) ∧ (ψθ))))
5 ancom 333 . . . 4 (((ψχ) ∧ (ψθ)) ↔ ((ψθ) ∧ (ψχ)))
65anbi2i 367 . . 3 ((((φχ) ∧ (φθ)) ∧ ((ψχ) ∧ (ψθ))) ↔ (((φχ) ∧ (φθ)) ∧ ((ψθ) ∧ (ψχ))))
7 an4 388 . . 3 ((((φχ) ∧ (φθ)) ∧ ((ψθ) ∧ (ψχ))) ↔ (((φχ) ∧ (ψθ)) ∧ ((φθ) ∧ (ψχ))))
86, 7bitr 151 . 2 ((((φχ) ∧ (φθ)) ∧ ((ψχ) ∧ (ψθ))) ↔ (((φχ) ∧ (ψθ)) ∧ ((φθ) ∧ (ψχ))))
91, 4, 83bitr 155 1 (((φψ) ∧ (χθ)) ↔ (((φχ) ∧ (ψθ)) ∧ ((φθ) ∧ (ψχ))))
Colors of variables: wff set class
Syntax hints:   ↔ wb 127   ∧ wa 196
This theorem is referenced by:  mulcmpblnr 3977
This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6
This theorem depends on definitions:  df-bi 128  df-an 198
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