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Mirrors > Home > MPE Home > Th. List > fcof1od | Structured version Visualization version GIF version |
Description: A function is bijective if a "retraction" and a "section" exist, see comments for fcof1 7307 and fcofo 7308. Formerly part of proof of fcof1o 7316. (Contributed by Mario Carneiro, 21-Mar-2015.) (Revised by AV, 15-Dec-2019.) |
Ref | Expression |
---|---|
fcof1od.f | ⊢ (𝜑 → 𝐹:𝐴⟶𝐵) |
fcof1od.g | ⊢ (𝜑 → 𝐺:𝐵⟶𝐴) |
fcof1od.a | ⊢ (𝜑 → (𝐺 ∘ 𝐹) = ( I ↾ 𝐴)) |
fcof1od.b | ⊢ (𝜑 → (𝐹 ∘ 𝐺) = ( I ↾ 𝐵)) |
Ref | Expression |
---|---|
fcof1od | ⊢ (𝜑 → 𝐹:𝐴–1-1-onto→𝐵) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fcof1od.f | . . 3 ⊢ (𝜑 → 𝐹:𝐴⟶𝐵) | |
2 | fcof1od.a | . . 3 ⊢ (𝜑 → (𝐺 ∘ 𝐹) = ( I ↾ 𝐴)) | |
3 | fcof1 7307 | . . 3 ⊢ ((𝐹:𝐴⟶𝐵 ∧ (𝐺 ∘ 𝐹) = ( I ↾ 𝐴)) → 𝐹:𝐴–1-1→𝐵) | |
4 | 1, 2, 3 | syl2anc 584 | . 2 ⊢ (𝜑 → 𝐹:𝐴–1-1→𝐵) |
5 | fcof1od.g | . . 3 ⊢ (𝜑 → 𝐺:𝐵⟶𝐴) | |
6 | fcof1od.b | . . 3 ⊢ (𝜑 → (𝐹 ∘ 𝐺) = ( I ↾ 𝐵)) | |
7 | fcofo 7308 | . . 3 ⊢ ((𝐹:𝐴⟶𝐵 ∧ 𝐺:𝐵⟶𝐴 ∧ (𝐹 ∘ 𝐺) = ( I ↾ 𝐵)) → 𝐹:𝐴–onto→𝐵) | |
8 | 1, 5, 6, 7 | syl3anc 1370 | . 2 ⊢ (𝜑 → 𝐹:𝐴–onto→𝐵) |
9 | df-f1o 6570 | . 2 ⊢ (𝐹:𝐴–1-1-onto→𝐵 ↔ (𝐹:𝐴–1-1→𝐵 ∧ 𝐹:𝐴–onto→𝐵)) | |
10 | 4, 8, 9 | sylanbrc 583 | 1 ⊢ (𝜑 → 𝐹:𝐴–1-1-onto→𝐵) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 = wceq 1537 I cid 5582 ↾ cres 5691 ∘ ccom 5693 ⟶wf 6559 –1-1→wf1 6560 –onto→wfo 6561 –1-1-onto→wf1o 6562 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1908 ax-6 1965 ax-7 2005 ax-8 2108 ax-9 2116 ax-10 2139 ax-11 2155 ax-12 2175 ax-ext 2706 ax-sep 5302 ax-nul 5312 ax-pr 5438 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3an 1088 df-tru 1540 df-fal 1550 df-ex 1777 df-nf 1781 df-sb 2063 df-mo 2538 df-eu 2567 df-clab 2713 df-cleq 2727 df-clel 2814 df-nfc 2890 df-ne 2939 df-ral 3060 df-rex 3069 df-rab 3434 df-v 3480 df-dif 3966 df-un 3968 df-in 3970 df-ss 3980 df-nul 4340 df-if 4532 df-sn 4632 df-pr 4634 df-op 4638 df-uni 4913 df-br 5149 df-opab 5211 df-mpt 5232 df-id 5583 df-xp 5695 df-rel 5696 df-cnv 5697 df-co 5698 df-dm 5699 df-rn 5700 df-res 5701 df-ima 5702 df-iota 6516 df-fun 6565 df-fn 6566 df-f 6567 df-f1 6568 df-fo 6569 df-f1o 6570 df-fv 6571 |
This theorem is referenced by: 2fcoidinvd 7315 fcof1o 7316 2fvidf1od 7318 catciso 18165 pmtrff1o 19496 evpmodpmf1o 21632 |
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