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Mirrors > Home > MPE Home > Th. List > Mathboxes > bj-df-ifc | Structured version Visualization version GIF version |
Description: Candidate definition for the conditional operator for classes. This is in line with the definition of a class as the extension of a predicate in df-clab 2712. We reprove the current df-if 4531 from it in bj-dfif 36563. (Contributed by BJ, 20-Sep-2019.) (Proof modification is discouraged.) |
Ref | Expression |
---|---|
bj-df-ifc | ⊢ if(𝜑, 𝐴, 𝐵) = {𝑥 ∣ if-(𝜑, 𝑥 ∈ 𝐴, 𝑥 ∈ 𝐵)} |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-if 4531 | . 2 ⊢ if(𝜑, 𝐴, 𝐵) = {𝑥 ∣ ((𝑥 ∈ 𝐴 ∧ 𝜑) ∨ (𝑥 ∈ 𝐵 ∧ ¬ 𝜑))} | |
2 | ancom 460 | . . . . 5 ⊢ ((𝑥 ∈ 𝐴 ∧ 𝜑) ↔ (𝜑 ∧ 𝑥 ∈ 𝐴)) | |
3 | ancom 460 | . . . . 5 ⊢ ((𝑥 ∈ 𝐵 ∧ ¬ 𝜑) ↔ (¬ 𝜑 ∧ 𝑥 ∈ 𝐵)) | |
4 | 2, 3 | orbi12i 914 | . . . 4 ⊢ (((𝑥 ∈ 𝐴 ∧ 𝜑) ∨ (𝑥 ∈ 𝐵 ∧ ¬ 𝜑)) ↔ ((𝜑 ∧ 𝑥 ∈ 𝐴) ∨ (¬ 𝜑 ∧ 𝑥 ∈ 𝐵))) |
5 | df-ifp 1063 | . . . 4 ⊢ (if-(𝜑, 𝑥 ∈ 𝐴, 𝑥 ∈ 𝐵) ↔ ((𝜑 ∧ 𝑥 ∈ 𝐴) ∨ (¬ 𝜑 ∧ 𝑥 ∈ 𝐵))) | |
6 | 4, 5 | bitr4i 278 | . . 3 ⊢ (((𝑥 ∈ 𝐴 ∧ 𝜑) ∨ (𝑥 ∈ 𝐵 ∧ ¬ 𝜑)) ↔ if-(𝜑, 𝑥 ∈ 𝐴, 𝑥 ∈ 𝐵)) |
7 | 6 | abbii 2806 | . 2 ⊢ {𝑥 ∣ ((𝑥 ∈ 𝐴 ∧ 𝜑) ∨ (𝑥 ∈ 𝐵 ∧ ¬ 𝜑))} = {𝑥 ∣ if-(𝜑, 𝑥 ∈ 𝐴, 𝑥 ∈ 𝐵)} |
8 | 1, 7 | eqtri 2762 | 1 ⊢ if(𝜑, 𝐴, 𝐵) = {𝑥 ∣ if-(𝜑, 𝑥 ∈ 𝐴, 𝑥 ∈ 𝐵)} |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 ∧ wa 395 ∨ wo 847 if-wif 1062 = wceq 1536 ∈ wcel 2105 {cab 2711 ifcif 4530 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1791 ax-4 1805 ax-5 1907 ax-6 1964 ax-7 2004 ax-9 2115 ax-ext 2705 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-ifp 1063 df-ex 1776 df-sb 2062 df-clab 2712 df-cleq 2726 df-if 4531 |
This theorem is referenced by: bj-dfif 36563 bj-ififc 36564 |
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