Theorem sseli

Description: Membership implication from subclass relationship. (Contributed by NM, 5-Aug-1993)

	Ref	Expression
Hypothesis	sseli.1	|- A C_ B
Assertion	sseli	|- ( C e. A -> C e. B )

Proof

Step	Hyp	Ref	Expression
1		sseli.1	|- A C_ B
2		ssel	|- ( A C_ B -> ( C e. A -> C e. B ) )
3	1 2	ax-mp	|- ( C e. A -> C e. B )