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Mirrors > Home > MPE Home > Th. List > elimhyp2v | Structured version Visualization version GIF version |
Description: Eliminate a hypothesis containing 2 class variables. (Contributed by NM, 14-Aug-1999.) |
Ref | Expression |
---|---|
elimhyp2v.1 | ⊢ (𝐴 = if(𝜑, 𝐴, 𝐶) → (𝜑 ↔ 𝜒)) |
elimhyp2v.2 | ⊢ (𝐵 = if(𝜑, 𝐵, 𝐷) → (𝜒 ↔ 𝜃)) |
elimhyp2v.3 | ⊢ (𝐶 = if(𝜑, 𝐴, 𝐶) → (𝜏 ↔ 𝜂)) |
elimhyp2v.4 | ⊢ (𝐷 = if(𝜑, 𝐵, 𝐷) → (𝜂 ↔ 𝜃)) |
elimhyp2v.5 | ⊢ 𝜏 |
Ref | Expression |
---|---|
elimhyp2v | ⊢ 𝜃 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | iftrue 4496 | . . . . . 6 ⊢ (𝜑 → if(𝜑, 𝐴, 𝐶) = 𝐴) | |
2 | 1 | eqcomd 2739 | . . . . 5 ⊢ (𝜑 → 𝐴 = if(𝜑, 𝐴, 𝐶)) |
3 | elimhyp2v.1 | . . . . 5 ⊢ (𝐴 = if(𝜑, 𝐴, 𝐶) → (𝜑 ↔ 𝜒)) | |
4 | 2, 3 | syl 17 | . . . 4 ⊢ (𝜑 → (𝜑 ↔ 𝜒)) |
5 | iftrue 4496 | . . . . . 6 ⊢ (𝜑 → if(𝜑, 𝐵, 𝐷) = 𝐵) | |
6 | 5 | eqcomd 2739 | . . . . 5 ⊢ (𝜑 → 𝐵 = if(𝜑, 𝐵, 𝐷)) |
7 | elimhyp2v.2 | . . . . 5 ⊢ (𝐵 = if(𝜑, 𝐵, 𝐷) → (𝜒 ↔ 𝜃)) | |
8 | 6, 7 | syl 17 | . . . 4 ⊢ (𝜑 → (𝜒 ↔ 𝜃)) |
9 | 4, 8 | bitrd 279 | . . 3 ⊢ (𝜑 → (𝜑 ↔ 𝜃)) |
10 | 9 | ibi 267 | . 2 ⊢ (𝜑 → 𝜃) |
11 | elimhyp2v.5 | . . 3 ⊢ 𝜏 | |
12 | iffalse 4499 | . . . . . 6 ⊢ (¬ 𝜑 → if(𝜑, 𝐴, 𝐶) = 𝐶) | |
13 | 12 | eqcomd 2739 | . . . . 5 ⊢ (¬ 𝜑 → 𝐶 = if(𝜑, 𝐴, 𝐶)) |
14 | elimhyp2v.3 | . . . . 5 ⊢ (𝐶 = if(𝜑, 𝐴, 𝐶) → (𝜏 ↔ 𝜂)) | |
15 | 13, 14 | syl 17 | . . . 4 ⊢ (¬ 𝜑 → (𝜏 ↔ 𝜂)) |
16 | iffalse 4499 | . . . . . 6 ⊢ (¬ 𝜑 → if(𝜑, 𝐵, 𝐷) = 𝐷) | |
17 | 16 | eqcomd 2739 | . . . . 5 ⊢ (¬ 𝜑 → 𝐷 = if(𝜑, 𝐵, 𝐷)) |
18 | elimhyp2v.4 | . . . . 5 ⊢ (𝐷 = if(𝜑, 𝐵, 𝐷) → (𝜂 ↔ 𝜃)) | |
19 | 17, 18 | syl 17 | . . . 4 ⊢ (¬ 𝜑 → (𝜂 ↔ 𝜃)) |
20 | 15, 19 | bitrd 279 | . . 3 ⊢ (¬ 𝜑 → (𝜏 ↔ 𝜃)) |
21 | 11, 20 | mpbii 232 | . 2 ⊢ (¬ 𝜑 → 𝜃) |
22 | 10, 21 | pm2.61i 182 | 1 ⊢ 𝜃 |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 205 = wceq 1542 ifcif 4490 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-8 2109 ax-9 2117 ax-ext 2704 |
This theorem depends on definitions: df-bi 206 df-an 398 df-or 847 df-ex 1783 df-sb 2069 df-clab 2711 df-cleq 2725 df-clel 2811 df-if 4491 |
This theorem is referenced by: omlsi 30395 |
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