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Theorem absneu 4207
 Description: Restricted existential uniqueness determined by a singleton. (Contributed by NM, 29-May-2006.)
Assertion
Ref Expression
absneu ((𝐴𝑉 ∧ {𝑥𝜑} = {𝐴}) → ∃!𝑥𝜑)

Proof of Theorem absneu
Dummy variable 𝑦 is distinct from all other variables.
StepHypRef Expression
1 sneq 4135 . . . . 5 (𝑦 = 𝐴 → {𝑦} = {𝐴})
21eqeq2d 2620 . . . 4 (𝑦 = 𝐴 → ({𝑥𝜑} = {𝑦} ↔ {𝑥𝜑} = {𝐴}))
32spcegv 3267 . . 3 (𝐴𝑉 → ({𝑥𝜑} = {𝐴} → ∃𝑦{𝑥𝜑} = {𝑦}))
43imp 444 . 2 ((𝐴𝑉 ∧ {𝑥𝜑} = {𝐴}) → ∃𝑦{𝑥𝜑} = {𝑦})
5 euabsn2 4204 . 2 (∃!𝑥𝜑 ↔ ∃𝑦{𝑥𝜑} = {𝑦})
64, 5sylibr 223 1 ((𝐴𝑉 ∧ {𝑥𝜑} = {𝐴}) → ∃!𝑥𝜑)
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ∧ wa 383   = wceq 1475  ∃wex 1695   ∈ wcel 1977  ∃!weu 2458  {cab 2596  {csn 4125 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-6 1875  ax-7 1922  ax-10 2006  ax-11 2021  ax-12 2034  ax-13 2234  ax-ext 2590 This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  df-tru 1478  df-ex 1696  df-nf 1701  df-sb 1868  df-eu 2462  df-clab 2597  df-cleq 2603  df-clel 2606  df-nfc 2740  df-v 3175  df-sn 4126 This theorem is referenced by:  rabsneu  4208
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