Description: If a class is contained in a difference, it is contained in the minuend. Deduction form of difss2 . (Contributed by David Moews, 1-May-2017)
Ref | Expression | ||
---|---|---|---|
Hypothesis | difss2d.1 | |
|
Assertion | difss2d | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | difss2d.1 | |
|
2 | difss2 | |
|
3 | 1 2 | syl | |