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Mirrors > Home > ILE Home > Th. List > vtoclb | GIF version |
Description: Implicit substitution of a class for a setvar variable. (Contributed by NM, 23-Dec-1993.) |
Ref | Expression |
---|---|
vtoclb.1 | ⊢ 𝐴 ∈ V |
vtoclb.2 | ⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜒)) |
vtoclb.3 | ⊢ (𝑥 = 𝐴 → (𝜓 ↔ 𝜃)) |
vtoclb.4 | ⊢ (𝜑 ↔ 𝜓) |
Ref | Expression |
---|---|
vtoclb | ⊢ (𝜒 ↔ 𝜃) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | vtoclb.1 | . 2 ⊢ 𝐴 ∈ V | |
2 | vtoclb.2 | . . 3 ⊢ (𝑥 = 𝐴 → (𝜑 ↔ 𝜒)) | |
3 | vtoclb.3 | . . 3 ⊢ (𝑥 = 𝐴 → (𝜓 ↔ 𝜃)) | |
4 | 2, 3 | bibi12d 235 | . 2 ⊢ (𝑥 = 𝐴 → ((𝜑 ↔ 𝜓) ↔ (𝜒 ↔ 𝜃))) |
5 | vtoclb.4 | . 2 ⊢ (𝜑 ↔ 𝜓) | |
6 | 1, 4, 5 | vtocl 2793 | 1 ⊢ (𝜒 ↔ 𝜃) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ↔ wb 105 = wceq 1353 ∈ wcel 2148 Vcvv 2739 |
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-5 1447 ax-gen 1449 ax-ie1 1493 ax-ie2 1494 ax-8 1504 ax-4 1510 ax-17 1526 ax-i9 1530 ax-ial 1534 ax-ext 2159 |
This theorem depends on definitions: df-bi 117 df-nf 1461 df-sb 1763 df-clab 2164 df-cleq 2170 df-clel 2173 df-v 2741 |
This theorem is referenced by: alexeq 2865 sbss 3533 |
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