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Description: A Cartesian product is included in the ordered pair universe. Exercise 3 of TakeutiZaring p. 25. (Contributed by NM, 2-Aug-1994)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | xpss |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ssv | ||
| 2 | ssv | ||
| 3 | xpss12 | ||
| 4 | 1 2 3 | mp2an |