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Description: A mapping is a class of ordered pairs. (Contributed by NM, 3-Aug-1994) (Proof shortened by Andrew Salmon, 17-Sep-2011)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | fssxp | |- ( F : A --> B -> F C_ ( A X. B ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | frel | |- ( F : A --> B -> Rel F ) |
|
| 2 | relssdmrn | |- ( Rel F -> F C_ ( dom F X. ran F ) ) |
|
| 3 | 1 2 | syl | |- ( F : A --> B -> F C_ ( dom F X. ran F ) ) |
| 4 | fdm | |- ( F : A --> B -> dom F = A ) |
|
| 5 | eqimss | |- ( dom F = A -> dom F C_ A ) |
|
| 6 | 4 5 | syl | |- ( F : A --> B -> dom F C_ A ) |
| 7 | frn | |- ( F : A --> B -> ran F C_ B ) |
|
| 8 | xpss12 | |- ( ( dom F C_ A /\ ran F C_ B ) -> ( dom F X. ran F ) C_ ( A X. B ) ) |
|
| 9 | 6 7 8 | syl2anc | |- ( F : A --> B -> ( dom F X. ran F ) C_ ( A X. B ) ) |
| 10 | 3 9 | sstrd | |- ( F : A --> B -> F C_ ( A X. B ) ) |