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Theorem rabsnt 3537
 Description: Truth implied by equality of a restricted class abstraction and a singleton. (Contributed by NM, 29-May-2006.) (Proof shortened by Mario Carneiro, 23-Dec-2016.)
Hypotheses
Ref Expression
rabsnt.1 𝐵 ∈ V
rabsnt.2 (𝑥 = 𝐵 → (𝜑𝜓))
Assertion
Ref Expression
rabsnt ({𝑥𝐴𝜑} = {𝐵} → 𝜓)
Distinct variable groups:   𝑥,𝐴   𝑥,𝐵   𝜓,𝑥
Allowed substitution hint:   𝜑(𝑥)

Proof of Theorem rabsnt
StepHypRef Expression
1 rabsnt.1 . . . 4 𝐵 ∈ V
21snid 3495 . . 3 𝐵 ∈ {𝐵}
3 id 19 . . 3 ({𝑥𝐴𝜑} = {𝐵} → {𝑥𝐴𝜑} = {𝐵})
42, 3syl5eleqr 2184 . 2 ({𝑥𝐴𝜑} = {𝐵} → 𝐵 ∈ {𝑥𝐴𝜑})
5 rabsnt.2 . . . 4 (𝑥 = 𝐵 → (𝜑𝜓))
65elrab 2785 . . 3 (𝐵 ∈ {𝑥𝐴𝜑} ↔ (𝐵𝐴𝜓))
76simprbi 270 . 2 (𝐵 ∈ {𝑥𝐴𝜑} → 𝜓)
84, 7syl 14 1 ({𝑥𝐴𝜑} = {𝐵} → 𝜓)
 Colors of variables: wff set class Syntax hints:   → wi 4   ↔ wb 104   = wceq 1296   ∈ wcel 1445  {crab 2374  Vcvv 2633  {csn 3466 This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 668  ax-5 1388  ax-7 1389  ax-gen 1390  ax-ie1 1434  ax-ie2 1435  ax-8 1447  ax-10 1448  ax-11 1449  ax-i12 1450  ax-bndl 1451  ax-4 1452  ax-17 1471  ax-i9 1475  ax-ial 1479  ax-i5r 1480  ax-ext 2077 This theorem depends on definitions:  df-bi 116  df-tru 1299  df-nf 1402  df-sb 1700  df-clab 2082  df-cleq 2088  df-clel 2091  df-nfc 2224  df-rab 2379  df-v 2635  df-sn 3472 This theorem is referenced by:  ontr2exmid  4369  onsucsssucexmid  4371  ordsoexmid  4406  unfiexmid  6708
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