Metamath Proof Explorer


Theorem r19.26-3

Description: Version of r19.26 with three quantifiers. (Contributed by FL, 22-Nov-2010)

Ref Expression
Assertion r19.26-3 ( ∀ 𝑥𝐴 ( 𝜑𝜓𝜒 ) ↔ ( ∀ 𝑥𝐴 𝜑 ∧ ∀ 𝑥𝐴 𝜓 ∧ ∀ 𝑥𝐴 𝜒 ) )

Proof

Step Hyp Ref Expression
1 r19.26 ( ∀ 𝑥𝐴 ( ( 𝜑𝜓 ) ∧ 𝜒 ) ↔ ( ∀ 𝑥𝐴 ( 𝜑𝜓 ) ∧ ∀ 𝑥𝐴 𝜒 ) )
2 r19.26 ( ∀ 𝑥𝐴 ( 𝜑𝜓 ) ↔ ( ∀ 𝑥𝐴 𝜑 ∧ ∀ 𝑥𝐴 𝜓 ) )
3 1 2 bianbi ( ∀ 𝑥𝐴 ( ( 𝜑𝜓 ) ∧ 𝜒 ) ↔ ( ( ∀ 𝑥𝐴 𝜑 ∧ ∀ 𝑥𝐴 𝜓 ) ∧ ∀ 𝑥𝐴 𝜒 ) )
4 df-3an ( ( 𝜑𝜓𝜒 ) ↔ ( ( 𝜑𝜓 ) ∧ 𝜒 ) )
5 4 ralbii ( ∀ 𝑥𝐴 ( 𝜑𝜓𝜒 ) ↔ ∀ 𝑥𝐴 ( ( 𝜑𝜓 ) ∧ 𝜒 ) )
6 df-3an ( ( ∀ 𝑥𝐴 𝜑 ∧ ∀ 𝑥𝐴 𝜓 ∧ ∀ 𝑥𝐴 𝜒 ) ↔ ( ( ∀ 𝑥𝐴 𝜑 ∧ ∀ 𝑥𝐴 𝜓 ) ∧ ∀ 𝑥𝐴 𝜒 ) )
7 3 5 6 3bitr4i ( ∀ 𝑥𝐴 ( 𝜑𝜓𝜒 ) ↔ ( ∀ 𝑥𝐴 𝜑 ∧ ∀ 𝑥𝐴 𝜓 ∧ ∀ 𝑥𝐴 𝜒 ) )