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| Mirrors > Home > MPE Home > Th. List > dfiso3 | Structured version Visualization version GIF version | ||
| Description: Alternate definition of an isomorphism of a category as a section in both directions. (Contributed by AV, 11-Apr-2020.) | 
| Ref | Expression | 
|---|---|
| dfiso3.b | ⊢ 𝐵 = (Base‘𝐶) | 
| dfiso3.h | ⊢ 𝐻 = (Hom ‘𝐶) | 
| dfiso3.i | ⊢ 𝐼 = (Iso‘𝐶) | 
| dfiso3.s | ⊢ 𝑆 = (Sect‘𝐶) | 
| dfiso3.c | ⊢ (𝜑 → 𝐶 ∈ Cat) | 
| dfiso3.x | ⊢ (𝜑 → 𝑋 ∈ 𝐵) | 
| dfiso3.y | ⊢ (𝜑 → 𝑌 ∈ 𝐵) | 
| dfiso3.f | ⊢ (𝜑 → 𝐹 ∈ (𝑋𝐻𝑌)) | 
| Ref | Expression | 
|---|---|
| dfiso3 | ⊢ (𝜑 → (𝐹 ∈ (𝑋𝐼𝑌) ↔ ∃𝑔 ∈ (𝑌𝐻𝑋)(𝑔(𝑌𝑆𝑋)𝐹 ∧ 𝐹(𝑋𝑆𝑌)𝑔))) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | dfiso3.b | . . 3 ⊢ 𝐵 = (Base‘𝐶) | |
| 2 | dfiso3.h | . . 3 ⊢ 𝐻 = (Hom ‘𝐶) | |
| 3 | dfiso3.c | . . 3 ⊢ (𝜑 → 𝐶 ∈ Cat) | |
| 4 | dfiso3.i | . . 3 ⊢ 𝐼 = (Iso‘𝐶) | |
| 5 | dfiso3.x | . . 3 ⊢ (𝜑 → 𝑋 ∈ 𝐵) | |
| 6 | dfiso3.y | . . 3 ⊢ (𝜑 → 𝑌 ∈ 𝐵) | |
| 7 | dfiso3.f | . . 3 ⊢ (𝜑 → 𝐹 ∈ (𝑋𝐻𝑌)) | |
| 8 | eqid 2737 | . . 3 ⊢ (Id‘𝐶) = (Id‘𝐶) | |
| 9 | eqid 2737 | . . 3 ⊢ (〈𝑋, 𝑌〉(comp‘𝐶)𝑋) = (〈𝑋, 𝑌〉(comp‘𝐶)𝑋) | |
| 10 | eqid 2737 | . . 3 ⊢ (〈𝑌, 𝑋〉(comp‘𝐶)𝑌) = (〈𝑌, 𝑋〉(comp‘𝐶)𝑌) | |
| 11 | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 | dfiso2 17816 | . 2 ⊢ (𝜑 → (𝐹 ∈ (𝑋𝐼𝑌) ↔ ∃𝑔 ∈ (𝑌𝐻𝑋)((𝑔(〈𝑋, 𝑌〉(comp‘𝐶)𝑋)𝐹) = ((Id‘𝐶)‘𝑋) ∧ (𝐹(〈𝑌, 𝑋〉(comp‘𝐶)𝑌)𝑔) = ((Id‘𝐶)‘𝑌)))) | 
| 12 | eqid 2737 | . . . . . 6 ⊢ (comp‘𝐶) = (comp‘𝐶) | |
| 13 | dfiso3.s | . . . . . 6 ⊢ 𝑆 = (Sect‘𝐶) | |
| 14 | 3 | adantr 480 | . . . . . 6 ⊢ ((𝜑 ∧ 𝑔 ∈ (𝑌𝐻𝑋)) → 𝐶 ∈ Cat) | 
| 15 | 6 | adantr 480 | . . . . . 6 ⊢ ((𝜑 ∧ 𝑔 ∈ (𝑌𝐻𝑋)) → 𝑌 ∈ 𝐵) | 
| 16 | 5 | adantr 480 | . . . . . 6 ⊢ ((𝜑 ∧ 𝑔 ∈ (𝑌𝐻𝑋)) → 𝑋 ∈ 𝐵) | 
| 17 | simpr 484 | . . . . . 6 ⊢ ((𝜑 ∧ 𝑔 ∈ (𝑌𝐻𝑋)) → 𝑔 ∈ (𝑌𝐻𝑋)) | |
| 18 | 7 | adantr 480 | . . . . . 6 ⊢ ((𝜑 ∧ 𝑔 ∈ (𝑌𝐻𝑋)) → 𝐹 ∈ (𝑋𝐻𝑌)) | 
| 19 | 1, 2, 12, 8, 13, 14, 15, 16, 17, 18 | issect2 17798 | . . . . 5 ⊢ ((𝜑 ∧ 𝑔 ∈ (𝑌𝐻𝑋)) → (𝑔(𝑌𝑆𝑋)𝐹 ↔ (𝐹(〈𝑌, 𝑋〉(comp‘𝐶)𝑌)𝑔) = ((Id‘𝐶)‘𝑌))) | 
| 20 | 1, 2, 12, 8, 13, 14, 16, 15, 18, 17 | issect2 17798 | . . . . 5 ⊢ ((𝜑 ∧ 𝑔 ∈ (𝑌𝐻𝑋)) → (𝐹(𝑋𝑆𝑌)𝑔 ↔ (𝑔(〈𝑋, 𝑌〉(comp‘𝐶)𝑋)𝐹) = ((Id‘𝐶)‘𝑋))) | 
| 21 | 19, 20 | anbi12d 632 | . . . 4 ⊢ ((𝜑 ∧ 𝑔 ∈ (𝑌𝐻𝑋)) → ((𝑔(𝑌𝑆𝑋)𝐹 ∧ 𝐹(𝑋𝑆𝑌)𝑔) ↔ ((𝐹(〈𝑌, 𝑋〉(comp‘𝐶)𝑌)𝑔) = ((Id‘𝐶)‘𝑌) ∧ (𝑔(〈𝑋, 𝑌〉(comp‘𝐶)𝑋)𝐹) = ((Id‘𝐶)‘𝑋)))) | 
| 22 | ancom 460 | . . . 4 ⊢ (((𝐹(〈𝑌, 𝑋〉(comp‘𝐶)𝑌)𝑔) = ((Id‘𝐶)‘𝑌) ∧ (𝑔(〈𝑋, 𝑌〉(comp‘𝐶)𝑋)𝐹) = ((Id‘𝐶)‘𝑋)) ↔ ((𝑔(〈𝑋, 𝑌〉(comp‘𝐶)𝑋)𝐹) = ((Id‘𝐶)‘𝑋) ∧ (𝐹(〈𝑌, 𝑋〉(comp‘𝐶)𝑌)𝑔) = ((Id‘𝐶)‘𝑌))) | |
| 23 | 21, 22 | bitr2di 288 | . . 3 ⊢ ((𝜑 ∧ 𝑔 ∈ (𝑌𝐻𝑋)) → (((𝑔(〈𝑋, 𝑌〉(comp‘𝐶)𝑋)𝐹) = ((Id‘𝐶)‘𝑋) ∧ (𝐹(〈𝑌, 𝑋〉(comp‘𝐶)𝑌)𝑔) = ((Id‘𝐶)‘𝑌)) ↔ (𝑔(𝑌𝑆𝑋)𝐹 ∧ 𝐹(𝑋𝑆𝑌)𝑔))) | 
| 24 | 23 | rexbidva 3177 | . 2 ⊢ (𝜑 → (∃𝑔 ∈ (𝑌𝐻𝑋)((𝑔(〈𝑋, 𝑌〉(comp‘𝐶)𝑋)𝐹) = ((Id‘𝐶)‘𝑋) ∧ (𝐹(〈𝑌, 𝑋〉(comp‘𝐶)𝑌)𝑔) = ((Id‘𝐶)‘𝑌)) ↔ ∃𝑔 ∈ (𝑌𝐻𝑋)(𝑔(𝑌𝑆𝑋)𝐹 ∧ 𝐹(𝑋𝑆𝑌)𝑔))) | 
| 25 | 11, 24 | bitrd 279 | 1 ⊢ (𝜑 → (𝐹 ∈ (𝑋𝐼𝑌) ↔ ∃𝑔 ∈ (𝑌𝐻𝑋)(𝑔(𝑌𝑆𝑋)𝐹 ∧ 𝐹(𝑋𝑆𝑌)𝑔))) | 
| Colors of variables: wff setvar class | 
| Syntax hints: → wi 4 ↔ wb 206 ∧ wa 395 = wceq 1540 ∈ wcel 2108 ∃wrex 3070 〈cop 4632 class class class wbr 5143 ‘cfv 6561 (class class class)co 7431 Basecbs 17247 Hom chom 17308 compcco 17309 Catccat 17707 Idccid 17708 Sectcsect 17788 Isociso 17790 | 
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1910 ax-6 1967 ax-7 2007 ax-8 2110 ax-9 2118 ax-10 2141 ax-11 2157 ax-12 2177 ax-ext 2708 ax-rep 5279 ax-sep 5296 ax-nul 5306 ax-pow 5365 ax-pr 5432 ax-un 7755 | 
| This theorem depends on definitions: df-bi 207 df-an 396 df-or 849 df-3an 1089 df-tru 1543 df-fal 1553 df-ex 1780 df-nf 1784 df-sb 2065 df-mo 2540 df-eu 2569 df-clab 2715 df-cleq 2729 df-clel 2816 df-nfc 2892 df-ne 2941 df-ral 3062 df-rex 3071 df-reu 3381 df-rab 3437 df-v 3482 df-sbc 3789 df-csb 3900 df-dif 3954 df-un 3956 df-in 3958 df-ss 3968 df-nul 4334 df-if 4526 df-pw 4602 df-sn 4627 df-pr 4629 df-op 4633 df-uni 4908 df-iun 4993 df-br 5144 df-opab 5206 df-mpt 5226 df-id 5578 df-xp 5691 df-rel 5692 df-cnv 5693 df-co 5694 df-dm 5695 df-rn 5696 df-res 5697 df-ima 5698 df-iota 6514 df-fun 6563 df-fn 6564 df-f 6565 df-f1 6566 df-fo 6567 df-f1o 6568 df-fv 6569 df-ov 7434 df-oprab 7435 df-mpo 7436 df-1st 8014 df-2nd 8015 df-sect 17791 df-inv 17792 df-iso 17793 | 
| This theorem is referenced by: thinciso 49117 | 
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