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Mirrors > Home > ILE Home > Th. List > 2eu2ex | GIF version |
Description: Double existential uniqueness. (Contributed by NM, 3-Dec-2001.) |
Ref | Expression |
---|---|
2eu2ex | ⊢ (∃!𝑥∃!𝑦𝜑 → ∃𝑥∃𝑦𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | euex 2066 | . 2 ⊢ (∃!𝑥∃!𝑦𝜑 → ∃𝑥∃!𝑦𝜑) | |
2 | euex 2066 | . . 3 ⊢ (∃!𝑦𝜑 → ∃𝑦𝜑) | |
3 | 2 | eximi 1610 | . 2 ⊢ (∃𝑥∃!𝑦𝜑 → ∃𝑥∃𝑦𝜑) |
4 | 1, 3 | syl 14 | 1 ⊢ (∃!𝑥∃!𝑦𝜑 → ∃𝑥∃𝑦𝜑) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∃wex 1502 ∃!weu 2036 |
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-io 710 ax-5 1457 ax-7 1458 ax-gen 1459 ax-ie1 1503 ax-ie2 1504 ax-8 1514 ax-10 1515 ax-11 1516 ax-i12 1517 ax-bndl 1519 ax-4 1520 ax-17 1536 ax-i9 1540 ax-ial 1544 ax-i5r 1545 |
This theorem depends on definitions: df-bi 117 df-nf 1471 df-sb 1773 df-eu 2039 |
This theorem is referenced by: (None) |
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