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Theorem 2eu2ex 2125
Description: Double existential uniqueness. (Contributed by NM, 3-Dec-2001.)
Assertion
Ref Expression
2eu2ex (∃!𝑥∃!𝑦𝜑 → ∃𝑥𝑦𝜑)

Proof of Theorem 2eu2ex
StepHypRef Expression
1 euex 2066 . 2 (∃!𝑥∃!𝑦𝜑 → ∃𝑥∃!𝑦𝜑)
2 euex 2066 . . 3 (∃!𝑦𝜑 → ∃𝑦𝜑)
32eximi 1610 . 2 (∃𝑥∃!𝑦𝜑 → ∃𝑥𝑦𝜑)
41, 3syl 14 1 (∃!𝑥∃!𝑦𝜑 → ∃𝑥𝑦𝜑)
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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