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	|- ( ph -> F : A --> B )
Assertion	fimassd	|- ( ph -> ( F " X ) C_ B )

Proof

Step	Hyp	Ref	Expression
1		fimassd.1	|- ( ph -> F : A --> B )
2		fimass	|- ( F : A --> B -> ( F " X ) C_ B )
3	1 2	syl	|- ( ph -> ( F " X ) C_ B )