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Mirrors > Home > ILE Home > Th. List > rexxfr2d | GIF version |
Description: Transfer universal quantification from a variable 𝑥 to another variable 𝑦 contained in expression 𝐴. (Contributed by Mario Carneiro, 20-Aug-2014.) (Proof shortened by Mario Carneiro, 19-Nov-2016.) |
Ref | Expression |
---|---|
ralxfr2d.1 | ⊢ ((𝜑 ∧ 𝑦 ∈ 𝐶) → 𝐴 ∈ 𝑉) |
ralxfr2d.2 | ⊢ (𝜑 → (𝑥 ∈ 𝐵 ↔ ∃𝑦 ∈ 𝐶 𝑥 = 𝐴)) |
ralxfr2d.3 | ⊢ ((𝜑 ∧ 𝑥 = 𝐴) → (𝜓 ↔ 𝜒)) |
Ref | Expression |
---|---|
rexxfr2d | ⊢ (𝜑 → (∃𝑥 ∈ 𝐵 𝜓 ↔ ∃𝑦 ∈ 𝐶 𝜒)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ralxfr2d.1 | . . . 4 ⊢ ((𝜑 ∧ 𝑦 ∈ 𝐶) → 𝐴 ∈ 𝑉) | |
2 | elisset 2766 | . . . 4 ⊢ (𝐴 ∈ 𝑉 → ∃𝑥 𝑥 = 𝐴) | |
3 | 1, 2 | syl 14 | . . 3 ⊢ ((𝜑 ∧ 𝑦 ∈ 𝐶) → ∃𝑥 𝑥 = 𝐴) |
4 | ralxfr2d.2 | . . . . . . . 8 ⊢ (𝜑 → (𝑥 ∈ 𝐵 ↔ ∃𝑦 ∈ 𝐶 𝑥 = 𝐴)) | |
5 | 4 | biimprd 158 | . . . . . . 7 ⊢ (𝜑 → (∃𝑦 ∈ 𝐶 𝑥 = 𝐴 → 𝑥 ∈ 𝐵)) |
6 | r19.23v 2599 | . . . . . . 7 ⊢ (∀𝑦 ∈ 𝐶 (𝑥 = 𝐴 → 𝑥 ∈ 𝐵) ↔ (∃𝑦 ∈ 𝐶 𝑥 = 𝐴 → 𝑥 ∈ 𝐵)) | |
7 | 5, 6 | sylibr 134 | . . . . . 6 ⊢ (𝜑 → ∀𝑦 ∈ 𝐶 (𝑥 = 𝐴 → 𝑥 ∈ 𝐵)) |
8 | 7 | r19.21bi 2578 | . . . . 5 ⊢ ((𝜑 ∧ 𝑦 ∈ 𝐶) → (𝑥 = 𝐴 → 𝑥 ∈ 𝐵)) |
9 | eleq1 2252 | . . . . 5 ⊢ (𝑥 = 𝐴 → (𝑥 ∈ 𝐵 ↔ 𝐴 ∈ 𝐵)) | |
10 | 8, 9 | mpbidi 151 | . . . 4 ⊢ ((𝜑 ∧ 𝑦 ∈ 𝐶) → (𝑥 = 𝐴 → 𝐴 ∈ 𝐵)) |
11 | 10 | exlimdv 1830 | . . 3 ⊢ ((𝜑 ∧ 𝑦 ∈ 𝐶) → (∃𝑥 𝑥 = 𝐴 → 𝐴 ∈ 𝐵)) |
12 | 3, 11 | mpd 13 | . 2 ⊢ ((𝜑 ∧ 𝑦 ∈ 𝐶) → 𝐴 ∈ 𝐵) |
13 | 4 | biimpa 296 | . 2 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐵) → ∃𝑦 ∈ 𝐶 𝑥 = 𝐴) |
14 | ralxfr2d.3 | . 2 ⊢ ((𝜑 ∧ 𝑥 = 𝐴) → (𝜓 ↔ 𝜒)) | |
15 | 12, 13, 14 | rexxfrd 4481 | 1 ⊢ (𝜑 → (∃𝑥 ∈ 𝐵 𝜓 ↔ ∃𝑦 ∈ 𝐶 𝜒)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 104 ↔ wb 105 = wceq 1364 ∃wex 1503 ∈ wcel 2160 ∀wral 2468 ∃wrex 2469 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-io 710 ax-5 1458 ax-7 1459 ax-gen 1460 ax-ie1 1504 ax-ie2 1505 ax-8 1515 ax-10 1516 ax-11 1517 ax-i12 1518 ax-bndl 1520 ax-4 1521 ax-17 1537 ax-i9 1541 ax-ial 1545 ax-i5r 1546 ax-ext 2171 |
This theorem depends on definitions: df-bi 117 df-tru 1367 df-nf 1472 df-sb 1774 df-clab 2176 df-cleq 2182 df-clel 2185 df-nfc 2321 df-ral 2473 df-rex 2474 df-v 2754 |
This theorem is referenced by: rexrn 5674 rexima 5776 cnptopresti 14215 cnptoprest 14216 txrest 14253 |
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