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| Mirrors > Home > ILE Home > Th. List > df-f1 | GIF version | ||
| Description: Define a one-to-one function. Compare Definition 6.15(5) of [TakeutiZaring] p. 27. We use their notation ("1-1" above the arrow). (Contributed by NM, 1-Aug-1994.) |
| Ref | Expression |
|---|---|
| df-f1 | ⊢ (𝐹:𝐴–1-1→𝐵 ↔ (𝐹:𝐴⟶𝐵 ∧ Fun ◡𝐹)) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cA | . . 3 class 𝐴 | |
| 2 | cB | . . 3 class 𝐵 | |
| 3 | cF | . . 3 class 𝐹 | |
| 4 | 1, 2, 3 | wf1 5323 | . 2 wff 𝐹:𝐴–1-1→𝐵 |
| 5 | 1, 2, 3 | wf 5322 | . . 3 wff 𝐹:𝐴⟶𝐵 |
| 6 | 3 | ccnv 4724 | . . . 4 class ◡𝐹 |
| 7 | 6 | wfun 5320 | . . 3 wff Fun ◡𝐹 |
| 8 | 5, 7 | wa 104 | . 2 wff (𝐹:𝐴⟶𝐵 ∧ Fun ◡𝐹) |
| 9 | 4, 8 | wb 105 | 1 wff (𝐹:𝐴–1-1→𝐵 ↔ (𝐹:𝐴⟶𝐵 ∧ Fun ◡𝐹)) |
| Colors of variables: wff set class |
| This definition is referenced by: f1eq1 5537 f1eq2 5538 f1eq3 5539 nff1 5540 dff12 5541 f1f 5542 f1ss 5548 f1ssr 5549 f1ssres 5551 f1cnvcnv 5553 f1co 5554 dff1o2 5588 f1f1orn 5594 f1imacnv 5600 fun11iun 5604 f11o 5617 f10 5618 f1o2ndf1 6392 ssdomg 6951 phplem4dom 7047 sbthlemi9 7163 casefun 7283 casef1 7288 djufun 7302 exmidfodomrlemim 7411 4sqlemffi 12968 ennnfonelemf1 13038 usgrislfuspgrdom 16040 subusgr 16125 trlf1 16238 trlres 16240 |
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