MPE Home Metamath Proof Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  MPE Home  >  Th. List  >  2exeu Structured version   Visualization version   GIF version

Theorem 2exeu 2651
Description: Double existential uniqueness implies double uniqueness quantification. (Contributed by NM, 3-Dec-2001.) (Proof shortened by Mario Carneiro, 22-Dec-2016.)
Assertion
Ref Expression
2exeu ((∃!𝑥𝑦𝜑 ∧ ∃!𝑦𝑥𝜑) → ∃!𝑥∃!𝑦𝜑)

Proof of Theorem 2exeu
StepHypRef Expression
1 eumo 2600 . . . 4 (∃!𝑥𝑦𝜑 → ∃*𝑥𝑦𝜑)
2 euex 2595 . . . . 5 (∃!𝑦𝜑 → ∃𝑦𝜑)
32moimi 2622 . . . 4 (∃*𝑥𝑦𝜑 → ∃*𝑥∃!𝑦𝜑)
41, 3syl 17 . . 3 (∃!𝑥𝑦𝜑 → ∃*𝑥∃!𝑦𝜑)
5 2euex 2646 . . 3 (∃!𝑦𝑥𝜑 → ∃𝑥∃!𝑦𝜑)
64, 5anim12ci 592 . 2 ((∃!𝑥𝑦𝜑 ∧ ∃!𝑦𝑥𝜑) → (∃𝑥∃!𝑦𝜑 ∧ ∃*𝑥∃!𝑦𝜑))
7 eu5 2597 . 2 (∃!𝑥∃!𝑦𝜑 ↔ (∃𝑥∃!𝑦𝜑 ∧ ∃*𝑥∃!𝑦𝜑))
86, 7sylibr 224 1 ((∃!𝑥𝑦𝜑 ∧ ∃!𝑦𝑥𝜑) → ∃!𝑥∃!𝑦𝜑)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 383  wex 1817  ∃!weu 2571  ∃*wmo 2572
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1835  ax-4 1850  ax-5 1952  ax-6 2018  ax-7 2054  ax-10 2132  ax-11 2147  ax-12 2160  ax-13 2355
This theorem depends on definitions:  df-bi 197  df-or 384  df-an 385  df-tru 1599  df-ex 1818  df-nf 1823  df-eu 2575  df-mo 2576
This theorem is referenced by:  2eu1  2655  2eu2  2656  2eu3  2657
  Copyright terms: Public domain W3C validator