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Mirrors > Home > ILE Home > Th. List > sbcom2v2 | GIF version |
Description: Lemma for proving sbcom2 1999. It is the same as sbcom2v 1997 but removes the distinct variable constraint on 𝑥 and 𝑦. (Contributed by Jim Kingdon, 19-Feb-2018.) |
Ref | Expression |
---|---|
sbcom2v2 | ⊢ ([𝑤 / 𝑧][𝑦 / 𝑥]𝜑 ↔ [𝑦 / 𝑥][𝑤 / 𝑧]𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sbcom2v 1997 | . . 3 ⊢ ([𝑤 / 𝑧][𝑦 / 𝑣][𝑣 / 𝑥]𝜑 ↔ [𝑦 / 𝑣][𝑤 / 𝑧][𝑣 / 𝑥]𝜑) | |
2 | sbcom2v 1997 | . . . 4 ⊢ ([𝑤 / 𝑧][𝑣 / 𝑥]𝜑 ↔ [𝑣 / 𝑥][𝑤 / 𝑧]𝜑) | |
3 | 2 | sbbii 1776 | . . 3 ⊢ ([𝑦 / 𝑣][𝑤 / 𝑧][𝑣 / 𝑥]𝜑 ↔ [𝑦 / 𝑣][𝑣 / 𝑥][𝑤 / 𝑧]𝜑) |
4 | 1, 3 | bitri 184 | . 2 ⊢ ([𝑤 / 𝑧][𝑦 / 𝑣][𝑣 / 𝑥]𝜑 ↔ [𝑦 / 𝑣][𝑣 / 𝑥][𝑤 / 𝑧]𝜑) |
5 | ax-17 1537 | . . . 4 ⊢ (𝜑 → ∀𝑣𝜑) | |
6 | 5 | sbco2vh 1957 | . . 3 ⊢ ([𝑦 / 𝑣][𝑣 / 𝑥]𝜑 ↔ [𝑦 / 𝑥]𝜑) |
7 | 6 | sbbii 1776 | . 2 ⊢ ([𝑤 / 𝑧][𝑦 / 𝑣][𝑣 / 𝑥]𝜑 ↔ [𝑤 / 𝑧][𝑦 / 𝑥]𝜑) |
8 | ax-17 1537 | . . 3 ⊢ ([𝑤 / 𝑧]𝜑 → ∀𝑣[𝑤 / 𝑧]𝜑) | |
9 | 8 | sbco2vh 1957 | . 2 ⊢ ([𝑦 / 𝑣][𝑣 / 𝑥][𝑤 / 𝑧]𝜑 ↔ [𝑦 / 𝑥][𝑤 / 𝑧]𝜑) |
10 | 4, 7, 9 | 3bitr3i 210 | 1 ⊢ ([𝑤 / 𝑧][𝑦 / 𝑥]𝜑 ↔ [𝑦 / 𝑥][𝑤 / 𝑧]𝜑) |
Colors of variables: wff set class |
Syntax hints: ↔ wb 105 [wsb 1773 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-io 710 ax-5 1458 ax-7 1459 ax-gen 1460 ax-ie1 1504 ax-ie2 1505 ax-8 1515 ax-10 1516 ax-11 1517 ax-i12 1518 ax-4 1521 ax-17 1537 ax-i9 1541 ax-ial 1545 ax-i5r 1546 |
This theorem depends on definitions: df-bi 117 df-nf 1472 df-sb 1774 |
This theorem is referenced by: sbcom2 1999 |
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