![]() |
Mathbox for Alexander van der Vekens |
< Previous
Next >
Nearby theorems |
|
Mirrors > Home > MPE Home > Th. List > Mathboxes > afv0nbfvbi | Structured version Visualization version GIF version |
Description: The function's value at an argument is an element of a set if and only if the value of the alternative function at this argument is an element of that set, if the set does not contain the empty set. (Contributed by Alexander van der Vekens, 25-May-2017.) |
Ref | Expression |
---|---|
afv0nbfvbi | ⊢ (∅ ∉ 𝐵 → ((𝐹'''𝐴) ∈ 𝐵 ↔ (𝐹‘𝐴) ∈ 𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | afvvfveq 42043 | . . 3 ⊢ ((𝐹'''𝐴) ∈ 𝐵 → (𝐹'''𝐴) = (𝐹‘𝐴)) | |
2 | eleq1 2894 | . . . 4 ⊢ ((𝐹'''𝐴) = (𝐹‘𝐴) → ((𝐹'''𝐴) ∈ 𝐵 ↔ (𝐹‘𝐴) ∈ 𝐵)) | |
3 | 2 | biimpd 221 | . . 3 ⊢ ((𝐹'''𝐴) = (𝐹‘𝐴) → ((𝐹'''𝐴) ∈ 𝐵 → (𝐹‘𝐴) ∈ 𝐵)) |
4 | 1, 3 | mpcom 38 | . 2 ⊢ ((𝐹'''𝐴) ∈ 𝐵 → (𝐹‘𝐴) ∈ 𝐵) |
5 | elnelne2 3113 | . . . . . 6 ⊢ (((𝐹‘𝐴) ∈ 𝐵 ∧ ∅ ∉ 𝐵) → (𝐹‘𝐴) ≠ ∅) | |
6 | 5 | ancoms 452 | . . . . 5 ⊢ ((∅ ∉ 𝐵 ∧ (𝐹‘𝐴) ∈ 𝐵) → (𝐹‘𝐴) ≠ ∅) |
7 | fvfundmfvn0 6472 | . . . . 5 ⊢ ((𝐹‘𝐴) ≠ ∅ → (𝐴 ∈ dom 𝐹 ∧ Fun (𝐹 ↾ {𝐴}))) | |
8 | df-dfat 42014 | . . . . . 6 ⊢ (𝐹 defAt 𝐴 ↔ (𝐴 ∈ dom 𝐹 ∧ Fun (𝐹 ↾ {𝐴}))) | |
9 | afvfundmfveq 42033 | . . . . . 6 ⊢ (𝐹 defAt 𝐴 → (𝐹'''𝐴) = (𝐹‘𝐴)) | |
10 | 8, 9 | sylbir 227 | . . . . 5 ⊢ ((𝐴 ∈ dom 𝐹 ∧ Fun (𝐹 ↾ {𝐴})) → (𝐹'''𝐴) = (𝐹‘𝐴)) |
11 | eleq1 2894 | . . . . . . 7 ⊢ ((𝐹‘𝐴) = (𝐹'''𝐴) → ((𝐹‘𝐴) ∈ 𝐵 ↔ (𝐹'''𝐴) ∈ 𝐵)) | |
12 | 11 | eqcoms 2833 | . . . . . 6 ⊢ ((𝐹'''𝐴) = (𝐹‘𝐴) → ((𝐹‘𝐴) ∈ 𝐵 ↔ (𝐹'''𝐴) ∈ 𝐵)) |
13 | 12 | biimpd 221 | . . . . 5 ⊢ ((𝐹'''𝐴) = (𝐹‘𝐴) → ((𝐹‘𝐴) ∈ 𝐵 → (𝐹'''𝐴) ∈ 𝐵)) |
14 | 6, 7, 10, 13 | 4syl 19 | . . . 4 ⊢ ((∅ ∉ 𝐵 ∧ (𝐹‘𝐴) ∈ 𝐵) → ((𝐹‘𝐴) ∈ 𝐵 → (𝐹'''𝐴) ∈ 𝐵)) |
15 | 14 | ex 403 | . . 3 ⊢ (∅ ∉ 𝐵 → ((𝐹‘𝐴) ∈ 𝐵 → ((𝐹‘𝐴) ∈ 𝐵 → (𝐹'''𝐴) ∈ 𝐵))) |
16 | 15 | pm2.43d 53 | . 2 ⊢ (∅ ∉ 𝐵 → ((𝐹‘𝐴) ∈ 𝐵 → (𝐹'''𝐴) ∈ 𝐵)) |
17 | 4, 16 | impbid2 218 | 1 ⊢ (∅ ∉ 𝐵 → ((𝐹'''𝐴) ∈ 𝐵 ↔ (𝐹‘𝐴) ∈ 𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 198 ∧ wa 386 = wceq 1656 ∈ wcel 2164 ≠ wne 2999 ∉ wnel 3102 ∅c0 4144 {csn 4397 dom cdm 5342 ↾ cres 5344 Fun wfun 6117 ‘cfv 6123 defAt wdfat 42011 '''cafv 42012 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1894 ax-4 1908 ax-5 2009 ax-6 2075 ax-7 2112 ax-8 2166 ax-9 2173 ax-10 2192 ax-11 2207 ax-12 2220 ax-13 2389 ax-ext 2803 ax-sep 5005 ax-nul 5013 ax-pow 5065 ax-pr 5127 |
This theorem depends on definitions: df-bi 199 df-an 387 df-or 879 df-3an 1113 df-tru 1660 df-fal 1670 df-ex 1879 df-nf 1883 df-sb 2068 df-mo 2605 df-eu 2640 df-clab 2812 df-cleq 2818 df-clel 2821 df-nfc 2958 df-ne 3000 df-nel 3103 df-ral 3122 df-rex 3123 df-rab 3126 df-v 3416 df-sbc 3663 df-csb 3758 df-dif 3801 df-un 3803 df-in 3805 df-ss 3812 df-nul 4145 df-if 4307 df-sn 4398 df-pr 4400 df-op 4404 df-uni 4659 df-int 4698 df-br 4874 df-opab 4936 df-id 5250 df-xp 5348 df-rel 5349 df-cnv 5350 df-co 5351 df-dm 5352 df-res 5354 df-iota 6086 df-fun 6125 df-fv 6131 df-aiota 41975 df-dfat 42014 df-afv 42015 |
This theorem is referenced by: aov0nbovbi 42090 |
Copyright terms: Public domain | W3C validator |