Metamath Proof Explorer


Theorem exdistr2

Description: Distribution of existential quantifiers. (Contributed by NM, 17-Mar-1995)

Ref Expression
Assertion exdistr2 ( ∃ 𝑥𝑦𝑧 ( 𝜑𝜓 ) ↔ ∃ 𝑥 ( 𝜑 ∧ ∃ 𝑦𝑧 𝜓 ) )

Proof

Step Hyp Ref Expression
1 19.42vv ( ∃ 𝑦𝑧 ( 𝜑𝜓 ) ↔ ( 𝜑 ∧ ∃ 𝑦𝑧 𝜓 ) )
2 1 exbii ( ∃ 𝑥𝑦𝑧 ( 𝜑𝜓 ) ↔ ∃ 𝑥 ( 𝜑 ∧ ∃ 𝑦𝑧 𝜓 ) )