Theorem difssd

Description: A difference of two classes is contained in the minuend. Deduction form of difss . (Contributed by David Moews, 1-May-2017)

	Ref	Expression
Assertion	difssd	$$⊢\phi \to A\setminus B\subseteq A$$

Proof

Step	Hyp	Ref	Expression
1		difss	$$⊢A\setminus B\subseteq A$$
2	1	a1i	$$⊢\phi \to A\setminus B\subseteq A$$