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Metamath Proof Explorer


Theorem iineq1d

Description: Equality theorem for indexed intersection. (Contributed by Glauco Siliprandi, 8-Apr-2021)

Ref Expression
Hypothesis iineq1d.1 φ A = B
Assertion iineq1d φ x A C = x B C

Proof

Step Hyp Ref Expression
1 iineq1d.1 φ A = B
2 iineq1 A = B x A C = x B C
3 1 2 syl φ x A C = x B C