Theorem 3bitr3rd 219

Description: Deduction from transitivity of biconditional. (Contributed by NM, 4-Aug-2006.)

Hypotheses

Ref	Expression
3bitr3d.1	⊢ (𝜑 → (𝜓 ↔ 𝜒))
3bitr3d.2	⊢ (𝜑 → (𝜓 ↔ 𝜃))
3bitr3d.3	⊢ (𝜑 → (𝜒 ↔ 𝜏))

Assertion

Ref	Expression
3bitr3rd	⊢ (𝜑 → (𝜏 ↔ 𝜃))

Proof of Theorem 3bitr3rd

Step	Hyp	Ref	Expression
1		3bitr3d.3	. 2 ⊢ (𝜑 → (𝜒 ↔ 𝜏))
2		3bitr3d.1	. . 3 ⊢ (𝜑 → (𝜓 ↔ 𝜒))
3		3bitr3d.2	. . 3 ⊢ (𝜑 → (𝜓 ↔ 𝜃))
4	2, 3	bitr3d 190	. 2 ⊢ (𝜑 → (𝜒 ↔ 𝜃))
5	1, 4	bitr3d 190	1 ⊢ (𝜑 → (𝜏 ↔ 𝜃))

This proof depends on syntax axioms:   → wi 4   ↔ wb 105

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108

This proof depends on definitions:  df-bi 117

This theorem is used by:  funconstss  5827  eqneg  9065  minclpr  12021  ballotfilemrv  13315  evenennn  13336  nmzsubg  14066  znidomb  15077  rpcxple2  16119  rpcxplt2  16120  wilthlem1  16198  lgslem1  16290