Users' Mathboxes Mathbox for Wolf Lammen < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  MPE Home  >  Th. List  >   Mathboxes  >  wl-mo2t Structured version   Visualization version   GIF version

Theorem wl-mo2t 33328
Description: Closed form of mo2 2477. (Contributed by Wolf Lammen, 18-Aug-2019.)
Assertion
Ref Expression
wl-mo2t (∀𝑥𝑦𝜑 → (∃*𝑥𝜑 ↔ ∃𝑦𝑥(𝜑𝑥 = 𝑦)))
Distinct variable group:   𝑥,𝑦
Allowed substitution hints:   𝜑(𝑥,𝑦)

Proof of Theorem wl-mo2t
Dummy variable 𝑢 is distinct from all other variables.
StepHypRef Expression
1 mo2v 2475 . 2 (∃*𝑥𝜑 ↔ ∃𝑢𝑥(𝜑𝑥 = 𝑢))
2 nfnf1 2029 . . . 4 𝑦𝑦𝜑
32nfal 2151 . . 3 𝑦𝑥𝑦𝜑
4 nfa1 2026 . . . 4 𝑥𝑥𝑦𝜑
5 sp 2051 . . . . 5 (∀𝑥𝑦𝜑 → Ⅎ𝑦𝜑)
6 nfvd 1842 . . . . 5 (∀𝑥𝑦𝜑 → Ⅎ𝑦 𝑥 = 𝑢)
75, 6nfimd 1821 . . . 4 (∀𝑥𝑦𝜑 → Ⅎ𝑦(𝜑𝑥 = 𝑢))
84, 7nfald 2163 . . 3 (∀𝑥𝑦𝜑 → Ⅎ𝑦𝑥(𝜑𝑥 = 𝑢))
9 equequ2 1951 . . . . . 6 (𝑢 = 𝑦 → (𝑥 = 𝑢𝑥 = 𝑦))
109imbi2d 330 . . . . 5 (𝑢 = 𝑦 → ((𝜑𝑥 = 𝑢) ↔ (𝜑𝑥 = 𝑦)))
1110albidv 1847 . . . 4 (𝑢 = 𝑦 → (∀𝑥(𝜑𝑥 = 𝑢) ↔ ∀𝑥(𝜑𝑥 = 𝑦)))
1211a1i 11 . . 3 (∀𝑥𝑦𝜑 → (𝑢 = 𝑦 → (∀𝑥(𝜑𝑥 = 𝑢) ↔ ∀𝑥(𝜑𝑥 = 𝑦))))
133, 8, 12cbvexd 2276 . 2 (∀𝑥𝑦𝜑 → (∃𝑢𝑥(𝜑𝑥 = 𝑢) ↔ ∃𝑦𝑥(𝜑𝑥 = 𝑦)))
141, 13syl5bb 272 1 (∀𝑥𝑦𝜑 → (∃*𝑥𝜑 ↔ ∃𝑦𝑥(𝜑𝑥 = 𝑦)))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 196  wal 1479  wex 1702  wnf 1706  ∃*wmo 2469
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1720  ax-4 1735  ax-5 1837  ax-6 1886  ax-7 1933  ax-10 2017  ax-11 2032  ax-12 2045  ax-13 2244
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-ex 1703  df-nf 1708  df-eu 2472  df-mo 2473
This theorem is referenced by:  wl-mo3t  33329
  Copyright terms: Public domain W3C validator