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Theorem ssabf 42211
Description: Subclass of a class abstraction. (Contributed by Glauco Siliprandi, 26-Jun-2021.)
Hypothesis
Ref Expression
ssabf.1 𝑥𝐴
Assertion
Ref Expression
ssabf (𝐴 ⊆ {𝑥𝜑} ↔ ∀𝑥(𝑥𝐴𝜑))

Proof of Theorem ssabf
StepHypRef Expression
1 ssabf.1 . . . 4 𝑥𝐴
21abid2f 2932 . . 3 {𝑥𝑥𝐴} = 𝐴
32sseq1i 3906 . 2 ({𝑥𝑥𝐴} ⊆ {𝑥𝜑} ↔ 𝐴 ⊆ {𝑥𝜑})
4 ss2ab 3950 . 2 ({𝑥𝑥𝐴} ⊆ {𝑥𝜑} ↔ ∀𝑥(𝑥𝐴𝜑))
53, 4bitr3i 280 1 (𝐴 ⊆ {𝑥𝜑} ↔ ∀𝑥(𝑥𝐴𝜑))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 209  wal 1540  wcel 2114  {cab 2717  wnfc 2880  wss 3844
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1802  ax-4 1816  ax-5 1917  ax-6 1975  ax-7 2020  ax-8 2116  ax-9 2124  ax-10 2145  ax-11 2162  ax-12 2179  ax-ext 2711
This theorem depends on definitions:  df-bi 210  df-an 400  df-or 847  df-tru 1545  df-ex 1787  df-nf 1791  df-sb 2075  df-clab 2718  df-cleq 2731  df-clel 2812  df-nfc 2882  df-v 3401  df-in 3851  df-ss 3861
This theorem is referenced by:  ssrabf  42225
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