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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 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | incom | ||
| 2 | inss1 | ||
| 3 | 1 2 | eqsstrri |