Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
Restricted quantification
Restricted universal and existential quantification
reximiaOLD
Metamath Proof Explorer
Description: Obsolete version of reximia as of 31-Oct-2024. (Contributed by NM , 10-Feb-1997) (Proof modification is discouraged.)
(New usage is discouraged.)
Ref
Expression
Hypothesis
reximiaOLD.1
⊢ x ∈ A → φ → ψ
Assertion
reximiaOLD
⊢ ∃ x ∈ A φ → ∃ x ∈ A ψ
Proof
Step
Hyp
Ref
Expression
1
reximiaOLD.1
⊢ x ∈ A → φ → ψ
2
rexim
⊢ ∀ x ∈ A φ → ψ → ∃ x ∈ A φ → ∃ x ∈ A ψ
3
2 1
mprg
⊢ ∃ x ∈ A φ → ∃ x ∈ A ψ