Metamath Proof Explorer


Theorem exdistr

Description: Distribution of existential quantifiers. See also exdistrv . (Contributed by NM, 9-Mar-1995)

Ref Expression
Assertion exdistr ( ∃ 𝑥𝑦 ( 𝜑𝜓 ) ↔ ∃ 𝑥 ( 𝜑 ∧ ∃ 𝑦 𝜓 ) )

Proof

Step Hyp Ref Expression
1 19.42v ( ∃ 𝑦 ( 𝜑𝜓 ) ↔ ( 𝜑 ∧ ∃ 𝑦 𝜓 ) )
2 1 exbii ( ∃ 𝑥𝑦 ( 𝜑𝜓 ) ↔ ∃ 𝑥 ( 𝜑 ∧ ∃ 𝑦 𝜓 ) )