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Theorem abvALT 3470
Description: Alternate proof of abv 3469, shorter but using more axioms. (Contributed by BJ, 19-Mar-2021.) (Proof modification is discouraged.) (New usage is discouraged.)
Assertion
Ref Expression
abvALT ({𝑥𝜑} = V ↔ ∀𝑥𝜑)

Proof of Theorem abvALT
Dummy variable 𝑦 is distinct from all other variables.
StepHypRef Expression
1 df-clab 2744 . . 3 (𝑦 ∈ {𝑥𝜑} ↔ [𝑦 / 𝑥]𝜑)
21albii 1852 . 2 (∀𝑦 𝑦 ∈ {𝑥𝜑} ↔ ∀𝑦[𝑦 / 𝑥]𝜑)
3 eqv 3467 . 2 ({𝑥𝜑} = V ↔ ∀𝑦 𝑦 ∈ {𝑥𝜑})
4 sb8v 2387 . 2 (∀𝑥𝜑 ↔ ∀𝑦[𝑦 / 𝑥]𝜑)
52, 3, 43bitr4i 306 1 ({𝑥𝜑} = V ↔ ∀𝑥𝜑)
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  wb 209  wal 1568   = wceq 1570  [wsb 2099  wcel 2146  {cab 2743  Vcvv 3457
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2148  ax-9 2156  ax-11 2195  ax-ext 2737
This proof depends on definitions:  df-bi 210  df-an 402  df-tru 1573  df-ex 1813  df-sb 2100  df-clab 2744  df-cleq 2757  df-clel 2840  df-v 3459
This theorem is used by: (None)
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