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Mirrors > Home > MPE Home > Th. List > 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.) Avoid ax-13 2363. (Revised by Gino Giotto, 19-May-2023.) |
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 4991 | . . 3 ⊢ (𝑦 ∈ ∪ 𝑥 ∈ {𝐴}𝐵 ↔ ∃𝑥 ∈ {𝐴}𝑦 ∈ 𝐵) | |
2 | iunxsngf.1 | . . . . 5 ⊢ Ⅎ𝑥𝐶 | |
3 | 2 | nfcri 2882 | . . . 4 ⊢ Ⅎ𝑥 𝑦 ∈ 𝐶 |
4 | iunxsngf.2 | . . . . 5 ⊢ (𝑥 = 𝐴 → 𝐵 = 𝐶) | |
5 | 4 | eleq2d 2811 | . . . 4 ⊢ (𝑥 = 𝐴 → (𝑦 ∈ 𝐵 ↔ 𝑦 ∈ 𝐶)) |
6 | 3, 5 | rexsngf 4666 | . . 3 ⊢ (𝐴 ∈ 𝑉 → (∃𝑥 ∈ {𝐴}𝑦 ∈ 𝐵 ↔ 𝑦 ∈ 𝐶)) |
7 | 1, 6 | bitrid 283 | . 2 ⊢ (𝐴 ∈ 𝑉 → (𝑦 ∈ ∪ 𝑥 ∈ {𝐴}𝐵 ↔ 𝑦 ∈ 𝐶)) |
8 | 7 | eqrdv 2722 | 1 ⊢ (𝐴 ∈ 𝑉 → ∪ 𝑥 ∈ {𝐴}𝐵 = 𝐶) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 = wceq 1533 ∈ wcel 2098 Ⅎwnfc 2875 ∃wrex 3062 {csn 4620 ∪ ciun 4987 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 ax-5 1905 ax-6 1963 ax-7 2003 ax-8 2100 ax-9 2108 ax-10 2129 ax-12 2163 ax-ext 2695 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 845 df-3an 1086 df-tru 1536 df-ex 1774 df-nf 1778 df-sb 2060 df-clab 2702 df-cleq 2716 df-clel 2802 df-nfc 2877 df-rex 3063 df-v 3468 df-sbc 3770 df-sn 4621 df-iun 4989 |
This theorem is referenced by: esum2dlem 33545 fiunelros 33627 iunxsnf 44205 |
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