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Mathbox for Alexander van der Vekens |
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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 46797 | . . 3 ⊢ ((𝐹'''𝐴) ∈ 𝐵 → (𝐹'''𝐴) = (𝐹‘𝐴)) | |
2 | eleq1 2814 | . . . 4 ⊢ ((𝐹'''𝐴) = (𝐹‘𝐴) → ((𝐹'''𝐴) ∈ 𝐵 ↔ (𝐹‘𝐴) ∈ 𝐵)) | |
3 | 2 | biimpd 228 | . . 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 3048 | . . . . . 6 ⊢ (((𝐹‘𝐴) ∈ 𝐵 ∧ ∅ ∉ 𝐵) → (𝐹‘𝐴) ≠ ∅) | |
6 | 5 | ancoms 457 | . . . . 5 ⊢ ((∅ ∉ 𝐵 ∧ (𝐹‘𝐴) ∈ 𝐵) → (𝐹‘𝐴) ≠ ∅) |
7 | fvfundmfvn0 6936 | . . . . 5 ⊢ ((𝐹‘𝐴) ≠ ∅ → (𝐴 ∈ dom 𝐹 ∧ Fun (𝐹 ↾ {𝐴}))) | |
8 | df-dfat 46768 | . . . . . 6 ⊢ (𝐹 defAt 𝐴 ↔ (𝐴 ∈ dom 𝐹 ∧ Fun (𝐹 ↾ {𝐴}))) | |
9 | afvfundmfveq 46787 | . . . . . 6 ⊢ (𝐹 defAt 𝐴 → (𝐹'''𝐴) = (𝐹‘𝐴)) | |
10 | 8, 9 | sylbir 234 | . . . . 5 ⊢ ((𝐴 ∈ dom 𝐹 ∧ Fun (𝐹 ↾ {𝐴})) → (𝐹'''𝐴) = (𝐹‘𝐴)) |
11 | eleq1 2814 | . . . . . . 7 ⊢ ((𝐹‘𝐴) = (𝐹'''𝐴) → ((𝐹‘𝐴) ∈ 𝐵 ↔ (𝐹'''𝐴) ∈ 𝐵)) | |
12 | 11 | eqcoms 2734 | . . . . . 6 ⊢ ((𝐹'''𝐴) = (𝐹‘𝐴) → ((𝐹‘𝐴) ∈ 𝐵 ↔ (𝐹'''𝐴) ∈ 𝐵)) |
13 | 12 | biimpd 228 | . . . . 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 411 | . . 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 225 | 1 ⊢ (∅ ∉ 𝐵 → ((𝐹'''𝐴) ∈ 𝐵 ↔ (𝐹‘𝐴) ∈ 𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ wa 394 = wceq 1534 ∈ wcel 2099 ≠ wne 2930 ∉ wnel 3036 ∅c0 4322 {csn 4623 dom cdm 5674 ↾ cres 5676 Fun wfun 6540 ‘cfv 6546 defAt wdfat 46765 '''cafv 46766 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1790 ax-4 1804 ax-5 1906 ax-6 1964 ax-7 2004 ax-8 2101 ax-9 2109 ax-10 2130 ax-11 2147 ax-12 2167 ax-ext 2697 ax-sep 5296 ax-nul 5303 ax-pr 5425 |
This theorem depends on definitions: df-bi 206 df-an 395 df-or 846 df-3an 1086 df-tru 1537 df-fal 1547 df-ex 1775 df-nf 1779 df-sb 2061 df-mo 2529 df-eu 2558 df-clab 2704 df-cleq 2718 df-clel 2803 df-nfc 2878 df-ne 2931 df-nel 3037 df-ral 3052 df-rex 3061 df-rab 3420 df-v 3464 df-sbc 3776 df-csb 3892 df-dif 3949 df-un 3951 df-in 3953 df-ss 3963 df-nul 4323 df-if 4524 df-sn 4624 df-pr 4626 df-op 4630 df-uni 4906 df-int 4947 df-br 5146 df-opab 5208 df-id 5572 df-xp 5680 df-rel 5681 df-cnv 5682 df-co 5683 df-dm 5684 df-res 5686 df-iota 6498 df-fun 6548 df-fv 6554 df-aiota 46734 df-dfat 46768 df-afv 46769 |
This theorem is referenced by: aov0nbovbi 46844 |
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