![]() |
Mathbox for Alexander van der Vekens |
< Previous
Next >
Nearby theorems |
|
Mirrors > Home > MPE Home > Th. List > Mathboxes > dfatco | Structured version Visualization version GIF version |
Description: The predicate "defined at" for a function composition. (Contributed by AV, 8-Sep-2022.) |
Ref | Expression |
---|---|
dfatco | ⊢ ((𝐺 defAt 𝑋 ∧ 𝐹 defAt (𝐺''''𝑋)) → (𝐹 ∘ 𝐺) defAt 𝑋) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfatcolem 46262 | . . . 4 ⊢ ((𝐺 defAt 𝑋 ∧ 𝐹 defAt (𝐺''''𝑋)) → ∃!𝑦 𝑋(𝐹 ∘ 𝐺)𝑦) | |
2 | euex 2571 | . . . 4 ⊢ (∃!𝑦 𝑋(𝐹 ∘ 𝐺)𝑦 → ∃𝑦 𝑋(𝐹 ∘ 𝐺)𝑦) | |
3 | 1, 2 | syl 17 | . . 3 ⊢ ((𝐺 defAt 𝑋 ∧ 𝐹 defAt (𝐺''''𝑋)) → ∃𝑦 𝑋(𝐹 ∘ 𝐺)𝑦) |
4 | df-dm 5686 | . . . . 5 ⊢ dom (𝐹 ∘ 𝐺) = {𝑥 ∣ ∃𝑦 𝑥(𝐹 ∘ 𝐺)𝑦} | |
5 | 4 | eleq2i 2825 | . . . 4 ⊢ (𝑋 ∈ dom (𝐹 ∘ 𝐺) ↔ 𝑋 ∈ {𝑥 ∣ ∃𝑦 𝑥(𝐹 ∘ 𝐺)𝑦}) |
6 | df-dfat 46126 | . . . . . . 7 ⊢ (𝐺 defAt 𝑋 ↔ (𝑋 ∈ dom 𝐺 ∧ Fun (𝐺 ↾ {𝑋}))) | |
7 | 6 | simplbi 498 | . . . . . 6 ⊢ (𝐺 defAt 𝑋 → 𝑋 ∈ dom 𝐺) |
8 | 7 | adantr 481 | . . . . 5 ⊢ ((𝐺 defAt 𝑋 ∧ 𝐹 defAt (𝐺''''𝑋)) → 𝑋 ∈ dom 𝐺) |
9 | breq1 5151 | . . . . . . 7 ⊢ (𝑥 = 𝑋 → (𝑥(𝐹 ∘ 𝐺)𝑦 ↔ 𝑋(𝐹 ∘ 𝐺)𝑦)) | |
10 | 9 | exbidv 1924 | . . . . . 6 ⊢ (𝑥 = 𝑋 → (∃𝑦 𝑥(𝐹 ∘ 𝐺)𝑦 ↔ ∃𝑦 𝑋(𝐹 ∘ 𝐺)𝑦)) |
11 | 10 | elabg 3666 | . . . . 5 ⊢ (𝑋 ∈ dom 𝐺 → (𝑋 ∈ {𝑥 ∣ ∃𝑦 𝑥(𝐹 ∘ 𝐺)𝑦} ↔ ∃𝑦 𝑋(𝐹 ∘ 𝐺)𝑦)) |
12 | 8, 11 | syl 17 | . . . 4 ⊢ ((𝐺 defAt 𝑋 ∧ 𝐹 defAt (𝐺''''𝑋)) → (𝑋 ∈ {𝑥 ∣ ∃𝑦 𝑥(𝐹 ∘ 𝐺)𝑦} ↔ ∃𝑦 𝑋(𝐹 ∘ 𝐺)𝑦)) |
13 | 5, 12 | bitrid 282 | . . 3 ⊢ ((𝐺 defAt 𝑋 ∧ 𝐹 defAt (𝐺''''𝑋)) → (𝑋 ∈ dom (𝐹 ∘ 𝐺) ↔ ∃𝑦 𝑋(𝐹 ∘ 𝐺)𝑦)) |
14 | 3, 13 | mpbird 256 | . 2 ⊢ ((𝐺 defAt 𝑋 ∧ 𝐹 defAt (𝐺''''𝑋)) → 𝑋 ∈ dom (𝐹 ∘ 𝐺)) |
15 | dfdfat2 46135 | . 2 ⊢ ((𝐹 ∘ 𝐺) defAt 𝑋 ↔ (𝑋 ∈ dom (𝐹 ∘ 𝐺) ∧ ∃!𝑦 𝑋(𝐹 ∘ 𝐺)𝑦)) | |
16 | 14, 1, 15 | sylanbrc 583 | 1 ⊢ ((𝐺 defAt 𝑋 ∧ 𝐹 defAt (𝐺''''𝑋)) → (𝐹 ∘ 𝐺) defAt 𝑋) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ wa 396 = wceq 1541 ∃wex 1781 ∈ wcel 2106 ∃!weu 2562 {cab 2709 {csn 4628 class class class wbr 5148 dom cdm 5676 ↾ cres 5678 ∘ ccom 5680 Fun wfun 6537 defAt wdfat 46123 ''''cafv2 46215 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1913 ax-6 1971 ax-7 2011 ax-8 2108 ax-9 2116 ax-10 2137 ax-11 2154 ax-12 2171 ax-ext 2703 ax-sep 5299 ax-nul 5306 ax-pow 5363 ax-pr 5427 |
This theorem depends on definitions: df-bi 206 df-an 397 df-or 846 df-3an 1089 df-tru 1544 df-fal 1554 df-ex 1782 df-nf 1786 df-sb 2068 df-mo 2534 df-eu 2563 df-clab 2710 df-cleq 2724 df-clel 2810 df-nfc 2885 df-ne 2941 df-ral 3062 df-rex 3071 df-rab 3433 df-v 3476 df-dif 3951 df-un 3953 df-in 3955 df-ss 3965 df-nul 4323 df-if 4529 df-sn 4629 df-pr 4631 df-op 4635 df-uni 4909 df-br 5149 df-opab 5211 df-id 5574 df-xp 5682 df-rel 5683 df-cnv 5684 df-co 5685 df-dm 5686 df-res 5688 df-iota 6495 df-fun 6545 df-fn 6546 df-dfat 46126 df-afv2 46216 |
This theorem is referenced by: afv2co2 46264 |
Copyright terms: Public domain | W3C validator |