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Mirrors > Home > ILE Home > Th. List > equsb3 | GIF version |
Description: Substitution applied to an atomic wff. (Contributed by Raph Levien and FL, 4-Dec-2005.) |
Ref | Expression |
---|---|
equsb3 | ⊢ ([𝑦 / 𝑥]𝑥 = 𝑧 ↔ 𝑦 = 𝑧) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | equsb3lem 1921 | . . 3 ⊢ ([𝑤 / 𝑥]𝑥 = 𝑧 ↔ 𝑤 = 𝑧) | |
2 | 1 | sbbii 1738 | . 2 ⊢ ([𝑦 / 𝑤][𝑤 / 𝑥]𝑥 = 𝑧 ↔ [𝑦 / 𝑤]𝑤 = 𝑧) |
3 | ax-17 1506 | . . 3 ⊢ (𝑥 = 𝑧 → ∀𝑤 𝑥 = 𝑧) | |
4 | 3 | sbco2vh 1916 | . 2 ⊢ ([𝑦 / 𝑤][𝑤 / 𝑥]𝑥 = 𝑧 ↔ [𝑦 / 𝑥]𝑥 = 𝑧) |
5 | equsb3lem 1921 | . 2 ⊢ ([𝑦 / 𝑤]𝑤 = 𝑧 ↔ 𝑦 = 𝑧) | |
6 | 2, 4, 5 | 3bitr3i 209 | 1 ⊢ ([𝑦 / 𝑥]𝑥 = 𝑧 ↔ 𝑦 = 𝑧) |
Colors of variables: wff set class |
Syntax hints: ↔ wb 104 [wsb 1735 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-io 698 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-10 1483 ax-11 1484 ax-i12 1485 ax-4 1487 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 |
This theorem depends on definitions: df-bi 116 df-nf 1437 df-sb 1736 |
This theorem is referenced by: sb8eu 2010 sb8euh 2020 sb8iota 5090 |
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