Metamath Proof Explorer


Theorem 19.34

Description: Theorem 19.34 of Margaris p. 90. (Contributed by NM, 12-Mar-1993)

Ref Expression
Assertion 19.34 ( ( ∀ 𝑥 𝜑 ∨ ∃ 𝑥 𝜓 ) → ∃ 𝑥 ( 𝜑𝜓 ) )

Proof

Step Hyp Ref Expression
1 19.2 ( ∀ 𝑥 𝜑 → ∃ 𝑥 𝜑 )
2 1 orim1i ( ( ∀ 𝑥 𝜑 ∨ ∃ 𝑥 𝜓 ) → ( ∃ 𝑥 𝜑 ∨ ∃ 𝑥 𝜓 ) )
3 19.43 ( ∃ 𝑥 ( 𝜑𝜓 ) ↔ ( ∃ 𝑥 𝜑 ∨ ∃ 𝑥 𝜓 ) )
4 2 3 sylibr ( ( ∀ 𝑥 𝜑 ∨ ∃ 𝑥 𝜓 ) → ∃ 𝑥 ( 𝜑𝜓 ) )