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Theorem bj-sseq 9931
Description: If two converse inclusions are characterized each by a formula, then equality is characterized by the conjunction of these formulas. (Contributed by BJ, 30-Nov-2019.)
Hypotheses
Ref Expression
bj-sseq.1 (𝜑 → (𝜓𝐴𝐵))
bj-sseq.2 (𝜑 → (𝜒𝐵𝐴))
Assertion
Ref Expression
bj-sseq (𝜑 → ((𝜓𝜒) ↔ 𝐴 = 𝐵))

Proof of Theorem bj-sseq
StepHypRef Expression
1 bj-sseq.1 . . 3 (𝜑 → (𝜓𝐴𝐵))
2 bj-sseq.2 . . 3 (𝜑 → (𝜒𝐵𝐴))
31, 2anbi12d 442 . 2 (𝜑 → ((𝜓𝜒) ↔ (𝐴𝐵𝐵𝐴)))
4 eqss 2960 . 2 (𝐴 = 𝐵 ↔ (𝐴𝐵𝐵𝐴))
53, 4syl6bbr 187 1 (𝜑 → ((𝜓𝜒) ↔ 𝐴 = 𝐵))
Colors of variables: wff set class
Syntax hints:  wi 4  wa 97  wb 98   = wceq 1243  wss 2917
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-5 1336  ax-7 1337  ax-gen 1338  ax-ie1 1382  ax-ie2 1383  ax-8 1395  ax-11 1397  ax-4 1400  ax-17 1419  ax-i9 1423  ax-ial 1427  ax-i5r 1428  ax-ext 2022
This theorem depends on definitions:  df-bi 110  df-nf 1350  df-sb 1646  df-clab 2027  df-cleq 2033  df-clel 2036  df-in 2924  df-ss 2931
This theorem is referenced by: (None)
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