Theorem 3anbi2i 1247

Description: Inference adding two conjuncts to each side of a biconditional. (Contributed by NM, 8-Sep-2006.)

Hypothesis

Ref	Expression
3anbi1i.1	⊢ (𝜑 ↔ 𝜓)

Assertion

Ref	Expression
3anbi2i	⊢ ((𝜒 ∧ 𝜑 ∧ 𝜃) ↔ (𝜒 ∧ 𝜓 ∧ 𝜃))

Proof of Theorem 3anbi2i

Step	Hyp	Ref	Expression
1		biid 250	. 2 ⊢ (𝜒 ↔ 𝜒)
2		3anbi1i.1	. 2 ⊢ (𝜑 ↔ 𝜓)
3		biid 250	. 2 ⊢ (𝜃 ↔ 𝜃)
4	1, 2, 3	3anbi123i 1244	1 ⊢ ((𝜒 ∧ 𝜑 ∧ 𝜃) ↔ (𝜒 ∧ 𝜓 ∧ 𝜃))

Syntax hints:   ↔ wb 195   ∧ w3a 1031

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 196  df-an 385  df-3an 1033

This theorem is referenced by:  f13dfv  6430  axgroth4  9533  fi1uzind  13134  fi1uzindOLD  13140  cusgra3v  25993  bnj543  30217  bnj916  30257  topdifinffinlem  32371