Metamath Proof Explorer


Theorem rsp2e

Description: Restricted specialization. (Contributed by FL, 4-Jun-2012) (Proof shortened by Wolf Lammen, 7-Jan-2020)

Ref Expression
Assertion rsp2e ( ( 𝑥𝐴𝑦𝐵𝜑 ) → ∃ 𝑥𝐴𝑦𝐵 𝜑 )

Proof

Step Hyp Ref Expression
1 rspe ( ( 𝑦𝐵𝜑 ) → ∃ 𝑦𝐵 𝜑 )
2 rspe ( ( 𝑥𝐴 ∧ ∃ 𝑦𝐵 𝜑 ) → ∃ 𝑥𝐴𝑦𝐵 𝜑 )
3 1 2 sylan2 ( ( 𝑥𝐴 ∧ ( 𝑦𝐵𝜑 ) ) → ∃ 𝑥𝐴𝑦𝐵 𝜑 )
4 3 3impb ( ( 𝑥𝐴𝑦𝐵𝜑 ) → ∃ 𝑥𝐴𝑦𝐵 𝜑 )