Theorem bianfd 544

Description: A wff conjoined with falsehood is false. (Contributed by NM, 27-Mar-1995.) (Proof shortened by Wolf Lammen, 5-Nov-2013.)

Hypothesis

Ref	Expression
bianfd.1	⊢ (𝜑 → ¬ 𝜓)

Assertion

Ref	Expression
bianfd	⊢ (𝜑 → (𝜓 ↔ (𝜓 ∧ 𝜒)))

Proof of Theorem bianfd

Step	Hyp	Ref	Expression
1		bianfd.1	. 2 ⊢ (𝜑 → ¬ 𝜓)
2	1	intnanrd 495	. 2 ⊢ (𝜑 → ¬ (𝜓 ∧ 𝜒))
3	1, 2	2falsed 379	1 ⊢ (𝜑 → (𝜓 ↔ (𝜓 ∧ 𝜒)))

This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ↔ wb 209   ∧ wa 401

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This proof depends on definitions:  df-bi 210  df-an 402

This theorem is used by:  eueq2  3675  eueq3  3676  axsepg3  35570  axsepg3ALT  35571