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Mirrors > Home > MPE Home > Th. List > Mathboxes > bj-sbievw | Structured version Visualization version GIF version |
Description: Lemma for substitution. Closed form of equsalvw 2010 and sbievw 2103. (Contributed by BJ, 23-Jul-2023.) |
Ref | Expression |
---|---|
bj-sbievw | ⊢ ([𝑦 / 𝑥](𝜑 ↔ 𝜓) → ([𝑦 / 𝑥]𝜑 ↔ 𝜓)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sb6 2093 | . 2 ⊢ ([𝑦 / 𝑥](𝜑 ↔ 𝜓) ↔ ∀𝑥(𝑥 = 𝑦 → (𝜑 ↔ 𝜓))) | |
2 | bj-sblem 34168 | . . 3 ⊢ (∀𝑥(𝑥 = 𝑦 → (𝜑 ↔ 𝜓)) → (∀𝑥(𝑥 = 𝑦 → 𝜑) ↔ (∃𝑥 𝑥 = 𝑦 → 𝜓))) | |
3 | sb6 2093 | . . 3 ⊢ ([𝑦 / 𝑥]𝜑 ↔ ∀𝑥(𝑥 = 𝑦 → 𝜑)) | |
4 | ax6ev 1972 | . . . 4 ⊢ ∃𝑥 𝑥 = 𝑦 | |
5 | 4 | a1bi 365 | . . 3 ⊢ (𝜓 ↔ (∃𝑥 𝑥 = 𝑦 → 𝜓)) |
6 | 2, 3, 5 | 3bitr4g 316 | . 2 ⊢ (∀𝑥(𝑥 = 𝑦 → (𝜑 ↔ 𝜓)) → ([𝑦 / 𝑥]𝜑 ↔ 𝜓)) |
7 | 1, 6 | sylbi 219 | 1 ⊢ ([𝑦 / 𝑥](𝜑 ↔ 𝜓) → ([𝑦 / 𝑥]𝜑 ↔ 𝜓)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 208 ∀wal 1535 ∃wex 1780 [wsb 2069 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-6 1970 ax-7 2015 |
This theorem depends on definitions: df-bi 209 df-an 399 df-ex 1781 df-sb 2070 |
This theorem is referenced by: (None) |
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