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Mirrors > Home > MPE Home > Th. List > Mathboxes > cdleme31sdnN | Structured version Visualization version GIF version |
Description: Part of proof of Lemma E in [Crawley] p. 113. (Contributed by NM, 31-Mar-2013.) (New usage is discouraged.) |
Ref | Expression |
---|---|
cdleme31sdn.c | ⊢ 𝐶 = ((𝑠 ∨ 𝑈) ∧ (𝑄 ∨ ((𝑃 ∨ 𝑠) ∧ 𝑊))) |
cdleme31sdn.d | ⊢ 𝐷 = ((𝑡 ∨ 𝑈) ∧ (𝑄 ∨ ((𝑃 ∨ 𝑡) ∧ 𝑊))) |
cdleme31sdn.n | ⊢ 𝑁 = if(𝑠 ≤ (𝑃 ∨ 𝑄), 𝐼, 𝐶) |
Ref | Expression |
---|---|
cdleme31sdnN | ⊢ 𝑁 = if(𝑠 ≤ (𝑃 ∨ 𝑄), 𝐼, ⦋𝑠 / 𝑡⦌𝐷) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cdleme31sdn.n | . 2 ⊢ 𝑁 = if(𝑠 ≤ (𝑃 ∨ 𝑄), 𝐼, 𝐶) | |
2 | biid 263 | . . 3 ⊢ (𝑠 ≤ (𝑃 ∨ 𝑄) ↔ 𝑠 ≤ (𝑃 ∨ 𝑄)) | |
3 | cdleme31sdn.d | . . . . 5 ⊢ 𝐷 = ((𝑡 ∨ 𝑈) ∧ (𝑄 ∨ ((𝑃 ∨ 𝑡) ∧ 𝑊))) | |
4 | cdleme31sdn.c | . . . . 5 ⊢ 𝐶 = ((𝑠 ∨ 𝑈) ∧ (𝑄 ∨ ((𝑃 ∨ 𝑠) ∧ 𝑊))) | |
5 | 3, 4 | cdleme31sc 37522 | . . . 4 ⊢ (𝑠 ∈ V → ⦋𝑠 / 𝑡⦌𝐷 = 𝐶) |
6 | 5 | elv 3501 | . . 3 ⊢ ⦋𝑠 / 𝑡⦌𝐷 = 𝐶 |
7 | 2, 6 | ifbieq2i 4493 | . 2 ⊢ if(𝑠 ≤ (𝑃 ∨ 𝑄), 𝐼, ⦋𝑠 / 𝑡⦌𝐷) = if(𝑠 ≤ (𝑃 ∨ 𝑄), 𝐼, 𝐶) |
8 | 1, 7 | eqtr4i 2849 | 1 ⊢ 𝑁 = if(𝑠 ≤ (𝑃 ∨ 𝑄), 𝐼, ⦋𝑠 / 𝑡⦌𝐷) |
Colors of variables: wff setvar class |
Syntax hints: = wceq 1537 Vcvv 3496 ⦋csb 3885 ifcif 4469 class class class wbr 5068 (class class class)co 7158 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2116 ax-9 2124 ax-10 2145 ax-11 2161 ax-12 2177 ax-ext 2795 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3an 1085 df-tru 1540 df-ex 1781 df-nf 1785 df-sb 2070 df-clab 2802 df-cleq 2816 df-clel 2895 df-nfc 2965 df-rab 3149 df-v 3498 df-sbc 3775 df-csb 3886 df-dif 3941 df-un 3943 df-in 3945 df-ss 3954 df-nul 4294 df-if 4470 df-sn 4570 df-pr 4572 df-op 4576 df-uni 4841 df-br 5069 df-iota 6316 df-fv 6365 df-ov 7161 |
This theorem is referenced by: (None) |
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