Theorem bj-sseq 15405

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	|- ( ph -> ( ps <-> A C_ B ) )
bj-sseq.2	|- ( ph -> ( ch <-> B C_ A ) )

Assertion

Ref	Expression
bj-sseq	|- ( ph -> ( ( ps /\ ch ) <-> A = B ) )

Proof of Theorem bj-sseq

Step	Hyp	Ref	Expression
1		bj-sseq.1	. . 3 |- ( ph -> ( ps <-> A C_ B ) )
2		bj-sseq.2	. . 3 |- ( ph -> ( ch <-> B C_ A ) )
3	1, 2	anbi12d 473	. 2 |- ( ph -> ( ( ps /\ ch ) <-> ( A C_ B /\ B C_ A ) ) )
4		eqss 3198	. 2 |- ( A = B <-> ( A C_ B /\ B C_ A ) )
5	3, 4	bitr4di 198	1 |- ( ph -> ( ( ps /\ ch ) <-> A = B ) )

Syntax hints:   -> wi 4   /\ wa 104   <-> wb 105   = wceq 1364   C_ wss 3157

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1461  ax-7 1462  ax-gen 1463  ax-ie1 1507  ax-ie2 1508  ax-8 1518  ax-11 1520  ax-4 1524  ax-17 1540  ax-i9 1544  ax-ial 1548  ax-i5r 1549  ax-ext 2178

This theorem depends on definitions:  df-bi 117  df-nf 1475  df-sb 1777  df-clab 2183  df-cleq 2189  df-clel 2192  df-in 3163  df-ss 3170

This theorem is referenced by: (None)