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Description: A class of ordered pairs of values in the form used by df-mpt is a function. (Contributed by NM, 17-Feb-2013)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | funopab4 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | simpr | ||
| 2 | 1 | ssopab2i | |
| 3 | funopabeq | ||
| 4 | funss | ||
| 5 | 2 3 4 | mp2 |