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| Mirrors > Home > NFE Home > Th. List > df-f1o | GIF version | ||
| Description: Define a one-to-one onto function. For equivalent definitions see dff1o2 5292, dff1o3 5293, dff1o4 5295, and dff1o5 5296. Compare Definition 6.15(6) of [TakeutiZaring] p. 27. We use their notation ("1-1" above the arrow and "onto" below the arrow). (Contributed by SF, 5-Jan-2015.) | 
| Ref | Expression | 
|---|---|
| df-f1o | ⊢ (F:A–1-1-onto→B ↔ (F:A–1-1→B ∧ F:A–onto→B)) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | cA | . . 3 class A | |
| 2 | cB | . . 3 class B | |
| 3 | cF | . . 3 class F | |
| 4 | 1, 2, 3 | wf1o 4781 | . 2 wff F:A–1-1-onto→B | 
| 5 | 1, 2, 3 | wf1 4779 | . . 3 wff F:A–1-1→B | 
| 6 | 1, 2, 3 | wfo 4780 | . . 3 wff F:A–onto→B | 
| 7 | 5, 6 | wa 358 | . 2 wff (F:A–1-1→B ∧ F:A–onto→B) | 
| 8 | 4, 7 | wb 176 | 1 wff (F:A–1-1-onto→B ↔ (F:A–1-1→B ∧ F:A–onto→B)) | 
| Colors of variables: wff setvar class | 
| This definition is referenced by: f1oeq1 5282 f1oeq2 5283 f1oeq3 5284 nff1o 5286 f1of1 5287 dff1o2 5292 dff1o5 5296 f1oco 5309 fo00 5319 f1o0 5320 dff1o6 5476 | 
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