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Mirrors > Home > MPE Home > Th. List > Mathboxes > bj-ax6e | Structured version Visualization version GIF version |
Description: Proof of ax6e 2392 (hence ax6 2393) from Tarski's system, ax-c9 35906, ax-c16 35908. Remark: ax-6 1961 is used only via its principal (unbundled) instance ax6v 1962. (Contributed by BJ, 22-Dec-2020.) (Proof modification is discouraged.) (New usage is discouraged.) |
Ref | Expression |
---|---|
bj-ax6e | ⊢ ∃𝑥 𝑥 = 𝑦 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 19.2 1972 | . . . 4 ⊢ (∀𝑥 𝑥 = 𝑦 → ∃𝑥 𝑥 = 𝑦) | |
2 | 1 | a1d 25 | . . 3 ⊢ (∀𝑥 𝑥 = 𝑦 → (𝑦 = 𝑧 → ∃𝑥 𝑥 = 𝑦)) |
3 | bj-ax6elem1 33896 | . . . 4 ⊢ (¬ ∀𝑥 𝑥 = 𝑦 → (𝑦 = 𝑧 → ∀𝑥 𝑦 = 𝑧)) | |
4 | bj-ax6elem2 33897 | . . . 4 ⊢ (∀𝑥 𝑦 = 𝑧 → ∃𝑥 𝑥 = 𝑦) | |
5 | 3, 4 | syl6 35 | . . 3 ⊢ (¬ ∀𝑥 𝑥 = 𝑦 → (𝑦 = 𝑧 → ∃𝑥 𝑥 = 𝑦)) |
6 | 2, 5 | pm2.61i 183 | . 2 ⊢ (𝑦 = 𝑧 → ∃𝑥 𝑥 = 𝑦) |
7 | ax6evr 2013 | . 2 ⊢ ∃𝑧 𝑦 = 𝑧 | |
8 | 6, 7 | exlimiiv 1923 | 1 ⊢ ∃𝑥 𝑥 = 𝑦 |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ∀wal 1526 ∃wex 1771 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1787 ax-4 1801 ax-5 1902 ax-6 1961 ax-7 2006 ax-10 2136 ax-12 2167 ax-13 2381 |
This theorem depends on definitions: df-bi 208 df-an 397 df-or 842 df-tru 1531 df-ex 1772 df-nf 1776 |
This theorem is referenced by: (None) |
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