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Metamath Proof Explorer

Theorem fimassd

Description: The image of a class is a subset of its codomain. (Contributed by Glauco Siliprandi, 23-Oct-2021)

		Ref	Expression
	Hypothesis	fimassd.1	$⊢ φ \to F : A ⟶ B$
	Assertion	fimassd	$⊢ φ \to F [X] \subseteq B$

Step	Hyp	Ref	Expression
1		fimassd.1	$⊢ φ \to F : A ⟶ B$
2		fimass	$⊢ F : A ⟶ B \to F [X] \subseteq B$
3	1 2	syl	$⊢ φ \to F [X] \subseteq B$