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Metamath Proof Explorer

Theorem iineq2d

Description: Equality deduction for indexed intersection. (Contributed by NM, 7-Dec-2011)

Ref Expression
Hypotheses iineq2d.1 ⊢ Ⅎ x φ
iineq2d.2 ⊢ φ ∧ x ∈ A → B = C
Assertion iineq2d ⊢ φ → ⋂ x ∈ A B = ⋂ x ∈ A C

Proof

Step Hyp Ref Expression
1 iineq2d.1 ⊢ Ⅎ x φ
2 iineq2d.2 ⊢ φ ∧ x ∈ A → B = C
3 1 2 ralrimia ⊢ φ → ∀ x ∈ A B = C
4 iineq2 ⊢ ∀ x ∈ A B = C → ⋂ x ∈ A B = ⋂ x ∈ A C
5 3 4 syl ⊢ φ → ⋂ x ∈ A B = ⋂ x ∈ A C