Theorem inss2

Description: The intersection of two classes is a subset of one of them. Part of Exercise 12 of TakeutiZaring p. 18. (Contributed by NM, 27-Apr-1994)

	Ref	Expression
Assertion	inss2	|- ( A i^i B ) C_ B

Proof

Step	Hyp	Ref	Expression
1		incom	|- ( B i^i A ) = ( A i^i B )
2		inss1	|- ( B i^i A ) C_ B
3	1 2	eqsstrri	|- ( A i^i B ) C_ B