Mathbox for Thierry Arnoux |
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Mirrors > Home > MPE Home > Th. List > Mathboxes > iunxsngf | Structured version Visualization version GIF version |
Description: A singleton index picks out an instance of an indexed union's argument. (Contributed by Mario Carneiro, 25-Jun-2016.) (Revised by Thierry Arnoux, 2-May-2020.) |
Ref | Expression |
---|---|
iunxsngf.1 | ⊢ Ⅎ𝑥𝐶 |
iunxsngf.2 | ⊢ (𝑥 = 𝐴 → 𝐵 = 𝐶) |
Ref | Expression |
---|---|
iunxsngf | ⊢ (𝐴 ∈ 𝑉 → ∪ 𝑥 ∈ {𝐴}𝐵 = 𝐶) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eliun 4460 | . . 3 ⊢ (𝑦 ∈ ∪ 𝑥 ∈ {𝐴}𝐵 ↔ ∃𝑥 ∈ {𝐴}𝑦 ∈ 𝐵) | |
2 | velsn 4141 | . . . . . . 7 ⊢ (𝑥 ∈ {𝐴} ↔ 𝑥 = 𝐴) | |
3 | 2 | anbi1i 727 | . . . . . 6 ⊢ ((𝑥 ∈ {𝐴} ∧ 𝑦 ∈ 𝐵) ↔ (𝑥 = 𝐴 ∧ 𝑦 ∈ 𝐵)) |
4 | 3 | exbii 1764 | . . . . 5 ⊢ (∃𝑥(𝑥 ∈ {𝐴} ∧ 𝑦 ∈ 𝐵) ↔ ∃𝑥(𝑥 = 𝐴 ∧ 𝑦 ∈ 𝐵)) |
5 | df-rex 2902 | . . . . 5 ⊢ (∃𝑥 ∈ {𝐴}𝑦 ∈ 𝐵 ↔ ∃𝑥(𝑥 ∈ {𝐴} ∧ 𝑦 ∈ 𝐵)) | |
6 | sbc5 3427 | . . . . 5 ⊢ ([𝐴 / 𝑥]𝑦 ∈ 𝐵 ↔ ∃𝑥(𝑥 = 𝐴 ∧ 𝑦 ∈ 𝐵)) | |
7 | 4, 5, 6 | 3bitr4i 291 | . . . 4 ⊢ (∃𝑥 ∈ {𝐴}𝑦 ∈ 𝐵 ↔ [𝐴 / 𝑥]𝑦 ∈ 𝐵) |
8 | nfcv 2751 | . . . . . 6 ⊢ Ⅎ𝑥𝑦 | |
9 | iunxsngf.1 | . . . . . 6 ⊢ Ⅎ𝑥𝐶 | |
10 | 8, 9 | nfel 2763 | . . . . 5 ⊢ Ⅎ𝑥 𝑦 ∈ 𝐶 |
11 | iunxsngf.2 | . . . . . 6 ⊢ (𝑥 = 𝐴 → 𝐵 = 𝐶) | |
12 | 11 | eleq2d 2673 | . . . . 5 ⊢ (𝑥 = 𝐴 → (𝑦 ∈ 𝐵 ↔ 𝑦 ∈ 𝐶)) |
13 | 10, 12 | sbciegf 3434 | . . . 4 ⊢ (𝐴 ∈ 𝑉 → ([𝐴 / 𝑥]𝑦 ∈ 𝐵 ↔ 𝑦 ∈ 𝐶)) |
14 | 7, 13 | syl5bb 271 | . . 3 ⊢ (𝐴 ∈ 𝑉 → (∃𝑥 ∈ {𝐴}𝑦 ∈ 𝐵 ↔ 𝑦 ∈ 𝐶)) |
15 | 1, 14 | syl5bb 271 | . 2 ⊢ (𝐴 ∈ 𝑉 → (𝑦 ∈ ∪ 𝑥 ∈ {𝐴}𝐵 ↔ 𝑦 ∈ 𝐶)) |
16 | 15 | eqrdv 2608 | 1 ⊢ (𝐴 ∈ 𝑉 → ∪ 𝑥 ∈ {𝐴}𝐵 = 𝐶) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 383 = wceq 1475 ∃wex 1695 ∈ wcel 1977 Ⅎwnfc 2738 ∃wrex 2897 [wsbc 3402 {csn 4125 ∪ ciun 4455 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1713 ax-4 1728 ax-5 1827 ax-6 1875 ax-7 1922 ax-10 2006 ax-11 2021 ax-12 2034 ax-13 2234 ax-ext 2590 |
This theorem depends on definitions: df-bi 196 df-or 384 df-an 385 df-3an 1033 df-tru 1478 df-ex 1696 df-nf 1701 df-sb 1868 df-clab 2597 df-cleq 2603 df-clel 2606 df-nfc 2740 df-ral 2901 df-rex 2902 df-v 3175 df-sbc 3403 df-sn 4126 df-iun 4457 |
This theorem is referenced by: esum2dlem 29481 fiunelros 29564 |
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