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Mirrors > Home > ILE Home > Th. List > ceqsrexv | GIF version |
Description: Elimination of a restricted existential quantifier, using implicit substitution. (Contributed by NM, 30-Apr-2004.) |
Ref | Expression |
---|---|
ceqsrexv.1 | ⊢ (x = A → (φ ↔ ψ)) |
Ref | Expression |
---|---|
ceqsrexv | ⊢ (A ∈ B → (∃x ∈ B (x = A ∧ φ) ↔ ψ)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-rex 2306 | . . 3 ⊢ (∃x ∈ B (x = A ∧ φ) ↔ ∃x(x ∈ B ∧ (x = A ∧ φ))) | |
2 | an12 495 | . . . 4 ⊢ ((x = A ∧ (x ∈ B ∧ φ)) ↔ (x ∈ B ∧ (x = A ∧ φ))) | |
3 | 2 | exbii 1493 | . . 3 ⊢ (∃x(x = A ∧ (x ∈ B ∧ φ)) ↔ ∃x(x ∈ B ∧ (x = A ∧ φ))) |
4 | 1, 3 | bitr4i 176 | . 2 ⊢ (∃x ∈ B (x = A ∧ φ) ↔ ∃x(x = A ∧ (x ∈ B ∧ φ))) |
5 | eleq1 2097 | . . . . 5 ⊢ (x = A → (x ∈ B ↔ A ∈ B)) | |
6 | ceqsrexv.1 | . . . . 5 ⊢ (x = A → (φ ↔ ψ)) | |
7 | 5, 6 | anbi12d 442 | . . . 4 ⊢ (x = A → ((x ∈ B ∧ φ) ↔ (A ∈ B ∧ ψ))) |
8 | 7 | ceqsexgv 2667 | . . 3 ⊢ (A ∈ B → (∃x(x = A ∧ (x ∈ B ∧ φ)) ↔ (A ∈ B ∧ ψ))) |
9 | 8 | bianabs 543 | . 2 ⊢ (A ∈ B → (∃x(x = A ∧ (x ∈ B ∧ φ)) ↔ ψ)) |
10 | 4, 9 | syl5bb 181 | 1 ⊢ (A ∈ B → (∃x ∈ B (x = A ∧ φ) ↔ ψ)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 97 ↔ wb 98 = wceq 1242 ∃wex 1378 ∈ wcel 1390 ∃wrex 2301 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 99 ax-ia2 100 ax-ia3 101 ax-io 629 ax-5 1333 ax-7 1334 ax-gen 1335 ax-ie1 1379 ax-ie2 1380 ax-8 1392 ax-10 1393 ax-11 1394 ax-i12 1395 ax-bndl 1396 ax-4 1397 ax-17 1416 ax-i9 1420 ax-ial 1424 ax-i5r 1425 ax-ext 2019 |
This theorem depends on definitions: df-bi 110 df-tru 1245 df-nf 1347 df-sb 1643 df-clab 2024 df-cleq 2030 df-clel 2033 df-nfc 2164 df-rex 2306 df-v 2553 |
This theorem is referenced by: ceqsrexbv 2669 ceqsrex2v 2670 f1oiso 5408 creur 7692 creui 7693 |
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