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Metamath Proof Explorer


Theorem imass2d

Description: Subset theorem for image. (Contributed by Glauco Siliprandi, 2-Jan-2022)

Ref Expression
Hypothesis imass2d.1 φ A B
Assertion imass2d φ C A C B

Proof

Step Hyp Ref Expression
1 imass2d.1 φ A B
2 imass2 A B C A C B
3 1 2 syl φ C A C B