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

Theorem mob 3584
Description: Equality implied by "at most one." (Contributed by NM, 18-Feb-2006.)
Hypotheses
Ref Expression
moi.1 (𝑥 = 𝐴 → (𝜑𝜓))
moi.2 (𝑥 = 𝐵 → (𝜑𝜒))
Assertion
Ref Expression
mob (((𝐴𝐶𝐵𝐷) ∧ ∃*𝑥𝜑𝜓) → (𝐴 = 𝐵𝜒))
Distinct variable groups:   𝑥,𝐴   𝑥,𝐵   𝜒,𝑥   𝜓,𝑥
Allowed substitution hints:   𝜑(𝑥)   𝐶(𝑥)   𝐷(𝑥)

Proof of Theorem mob
StepHypRef Expression
1 elex 3400 . . . . 5 (𝐵𝐷𝐵 ∈ V)
2 nfv 2010 . . . . . . . . . 10 𝑥 𝐵 ∈ V
3 nfmo1 2596 . . . . . . . . . 10 𝑥∃*𝑥𝜑
4 nfv 2010 . . . . . . . . . 10 𝑥𝜓
52, 3, 4nf3an 2001 . . . . . . . . 9 𝑥(𝐵 ∈ V ∧ ∃*𝑥𝜑𝜓)
6 nfv 2010 . . . . . . . . 9 𝑥(𝐴 = 𝐵𝜒)
75, 6nfim 1996 . . . . . . . 8 𝑥((𝐵 ∈ V ∧ ∃*𝑥𝜑𝜓) → (𝐴 = 𝐵𝜒))
8 moi.1 . . . . . . . . . 10 (𝑥 = 𝐴 → (𝜑𝜓))
983anbi3d 1567 . . . . . . . . 9 (𝑥 = 𝐴 → ((𝐵 ∈ V ∧ ∃*𝑥𝜑𝜑) ↔ (𝐵 ∈ V ∧ ∃*𝑥𝜑𝜓)))
10 eqeq1 2803 . . . . . . . . . 10 (𝑥 = 𝐴 → (𝑥 = 𝐵𝐴 = 𝐵))
1110bibi1d 335 . . . . . . . . 9 (𝑥 = 𝐴 → ((𝑥 = 𝐵𝜒) ↔ (𝐴 = 𝐵𝜒)))
129, 11imbi12d 336 . . . . . . . 8 (𝑥 = 𝐴 → (((𝐵 ∈ V ∧ ∃*𝑥𝜑𝜑) → (𝑥 = 𝐵𝜒)) ↔ ((𝐵 ∈ V ∧ ∃*𝑥𝜑𝜓) → (𝐴 = 𝐵𝜒))))
13 moi.2 . . . . . . . . 9 (𝑥 = 𝐵 → (𝜑𝜒))
1413mob2 3582 . . . . . . . 8 ((𝐵 ∈ V ∧ ∃*𝑥𝜑𝜑) → (𝑥 = 𝐵𝜒))
157, 12, 14vtoclg1f 3452 . . . . . . 7 (𝐴𝐶 → ((𝐵 ∈ V ∧ ∃*𝑥𝜑𝜓) → (𝐴 = 𝐵𝜒)))
1615com12 32 . . . . . 6 ((𝐵 ∈ V ∧ ∃*𝑥𝜑𝜓) → (𝐴𝐶 → (𝐴 = 𝐵𝜒)))
17163expib 1153 . . . . 5 (𝐵 ∈ V → ((∃*𝑥𝜑𝜓) → (𝐴𝐶 → (𝐴 = 𝐵𝜒))))
181, 17syl 17 . . . 4 (𝐵𝐷 → ((∃*𝑥𝜑𝜓) → (𝐴𝐶 → (𝐴 = 𝐵𝜒))))
1918com3r 87 . . 3 (𝐴𝐶 → (𝐵𝐷 → ((∃*𝑥𝜑𝜓) → (𝐴 = 𝐵𝜒))))
2019imp 396 . 2 ((𝐴𝐶𝐵𝐷) → ((∃*𝑥𝜑𝜓) → (𝐴 = 𝐵𝜒)))
21203impib 1145 1 (((𝐴𝐶𝐵𝐷) ∧ ∃*𝑥𝜑𝜓) → (𝐴 = 𝐵𝜒))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 198  wa 385  w3a 1108   = wceq 1653  wcel 2157  ∃*wmo 2589  Vcvv 3385
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1891  ax-4 1905  ax-5 2006  ax-6 2072  ax-7 2107  ax-9 2166  ax-10 2185  ax-11 2200  ax-12 2213  ax-ext 2777
This theorem depends on definitions:  df-bi 199  df-an 386  df-or 875  df-3an 1110  df-tru 1657  df-ex 1876  df-nf 1880  df-sb 2065  df-mo 2591  df-clab 2786  df-cleq 2792  df-clel 2795  df-nfc 2930  df-v 3387
This theorem is referenced by:  moi  3585  rmob  3724
  Copyright terms: Public domain W3C validator