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Mirrors > Home > MPE Home > Th. List > cgsexg | Structured version Visualization version GIF version |
Description: Implicit substitution inference for general classes. (Contributed by NM, 26-Aug-2007.) |
Ref | Expression |
---|---|
cgsexg.1 | ⊢ (𝑥 = 𝐴 → 𝜒) |
cgsexg.2 | ⊢ (𝜒 → (𝜑 ↔ 𝜓)) |
Ref | Expression |
---|---|
cgsexg | ⊢ (𝐴 ∈ 𝑉 → (∃𝑥(𝜒 ∧ 𝜑) ↔ 𝜓)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cgsexg.2 | . . . 4 ⊢ (𝜒 → (𝜑 ↔ 𝜓)) | |
2 | 1 | biimpa 479 | . . 3 ⊢ ((𝜒 ∧ 𝜑) → 𝜓) |
3 | 2 | exlimiv 1925 | . 2 ⊢ (∃𝑥(𝜒 ∧ 𝜑) → 𝜓) |
4 | elisset 3504 | . . . 4 ⊢ (𝐴 ∈ 𝑉 → ∃𝑥 𝑥 = 𝐴) | |
5 | cgsexg.1 | . . . . 5 ⊢ (𝑥 = 𝐴 → 𝜒) | |
6 | 5 | eximi 1829 | . . . 4 ⊢ (∃𝑥 𝑥 = 𝐴 → ∃𝑥𝜒) |
7 | 4, 6 | syl 17 | . . 3 ⊢ (𝐴 ∈ 𝑉 → ∃𝑥𝜒) |
8 | 1 | biimprcd 252 | . . . . 5 ⊢ (𝜓 → (𝜒 → 𝜑)) |
9 | 8 | ancld 553 | . . . 4 ⊢ (𝜓 → (𝜒 → (𝜒 ∧ 𝜑))) |
10 | 9 | eximdv 1912 | . . 3 ⊢ (𝜓 → (∃𝑥𝜒 → ∃𝑥(𝜒 ∧ 𝜑))) |
11 | 7, 10 | syl5com 31 | . 2 ⊢ (𝐴 ∈ 𝑉 → (𝜓 → ∃𝑥(𝜒 ∧ 𝜑))) |
12 | 3, 11 | impbid2 228 | 1 ⊢ (𝐴 ∈ 𝑉 → (∃𝑥(𝜒 ∧ 𝜑) ↔ 𝜓)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 208 ∧ wa 398 = wceq 1531 ∃wex 1774 ∈ wcel 2108 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1790 ax-4 1804 ax-5 1905 ax-6 1964 ax-7 2009 ax-8 2110 ax-9 2118 ax-ext 2791 |
This theorem depends on definitions: df-bi 209 df-an 399 df-ex 1775 df-cleq 2812 df-clel 2891 |
This theorem is referenced by: ceqsexgv 3645 |
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