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Mirrors > Home > ILE Home > Th. List > f1ff1 | Unicode version |
Description: If a function is one-to-one from to and is also a function from to , then it is a one-to-one function from to . (Contributed by BJ, 4-Jul-2022.) |
Ref | Expression |
---|---|
f1ff1 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | frn 5346 | . 2 | |
2 | f1ssr 5400 | . 2 | |
3 | 1, 2 | sylan2 284 | 1 |
Colors of variables: wff set class |
Syntax hints: wi 4 wa 103 wss 3116 crn 4605 wf 5184 wf1 5185 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 |
This theorem depends on definitions: df-bi 116 df-f 5192 df-f1 5193 |
This theorem is referenced by: f1resf1 5403 inresflem 7025 |
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