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Mirrors > Home > MPE Home > Th. List > abv | Structured version Visualization version GIF version |
Description: The class of sets verifying a property is the universal class if and only if that property is a tautology. The reverse implication (bj-abv 35781) requires fewer axioms. (Contributed by BJ, 19-Mar-2021.) Avoid df-clel 2810, ax-8 2108. (Revised by Gino Giotto, 30-Aug-2024.) (Proof shortened by BJ, 30-Aug-2024.) |
Ref | Expression |
---|---|
abv | ⊢ ({𝑥 ∣ 𝜑} = V ↔ ∀𝑥𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfcleq 2725 | . . 3 ⊢ ({𝑥 ∣ 𝜑} = {𝑥 ∣ ⊤} ↔ ∀𝑦(𝑦 ∈ {𝑥 ∣ 𝜑} ↔ 𝑦 ∈ {𝑥 ∣ ⊤})) | |
2 | vextru 2716 | . . . . . 6 ⊢ 𝑦 ∈ {𝑥 ∣ ⊤} | |
3 | 2 | tbt 369 | . . . . 5 ⊢ (𝑦 ∈ {𝑥 ∣ 𝜑} ↔ (𝑦 ∈ {𝑥 ∣ 𝜑} ↔ 𝑦 ∈ {𝑥 ∣ ⊤})) |
4 | df-clab 2710 | . . . . 5 ⊢ (𝑦 ∈ {𝑥 ∣ 𝜑} ↔ [𝑦 / 𝑥]𝜑) | |
5 | 3, 4 | bitr3i 276 | . . . 4 ⊢ ((𝑦 ∈ {𝑥 ∣ 𝜑} ↔ 𝑦 ∈ {𝑥 ∣ ⊤}) ↔ [𝑦 / 𝑥]𝜑) |
6 | 5 | albii 1821 | . . 3 ⊢ (∀𝑦(𝑦 ∈ {𝑥 ∣ 𝜑} ↔ 𝑦 ∈ {𝑥 ∣ ⊤}) ↔ ∀𝑦[𝑦 / 𝑥]𝜑) |
7 | 1, 6 | bitri 274 | . 2 ⊢ ({𝑥 ∣ 𝜑} = {𝑥 ∣ ⊤} ↔ ∀𝑦[𝑦 / 𝑥]𝜑) |
8 | dfv2 3477 | . . 3 ⊢ V = {𝑥 ∣ ⊤} | |
9 | 8 | eqeq2i 2745 | . 2 ⊢ ({𝑥 ∣ 𝜑} = V ↔ {𝑥 ∣ 𝜑} = {𝑥 ∣ ⊤}) |
10 | sb8v 2348 | . 2 ⊢ (∀𝑥𝜑 ↔ ∀𝑦[𝑦 / 𝑥]𝜑) | |
11 | 7, 9, 10 | 3bitr4i 302 | 1 ⊢ ({𝑥 ∣ 𝜑} = V ↔ ∀𝑥𝜑) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 205 ∀wal 1539 = wceq 1541 ⊤wtru 1542 [wsb 2067 ∈ wcel 2106 {cab 2709 Vcvv 3474 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1913 ax-6 1971 ax-7 2011 ax-9 2116 ax-11 2154 ax-ext 2703 |
This theorem depends on definitions: df-bi 206 df-an 397 df-tru 1544 df-ex 1782 df-sb 2068 df-clab 2710 df-cleq 2724 df-v 3476 |
This theorem is referenced by: dfnf5 4377 |
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