Theorem tpssbd 32488

Description: If an ordered triple is a subset of a class, the second element of the triple is an element of that class. (Contributed by Thierry Arnoux, 2-Nov-2025.)

Hypotheses

Ref	Expression
tpssbd.1	⊢ (𝜑 → 𝐵 ∈ 𝑉)
tpssbd.2	⊢ (𝜑 → {𝐴, 𝐵, 𝐶} ⊆ 𝐷)

Assertion

Ref	Expression
tpssbd	⊢ (𝜑 → 𝐵 ∈ 𝐷)

Proof of Theorem tpssbd

Step	Hyp	Ref	Expression
1		tpssbd.1	. 2 ⊢ (𝜑 → 𝐵 ∈ 𝑉)
2		tprot 4729	. . 3 ⊢ {𝐴, 𝐵, 𝐶} = {𝐵, 𝐶, 𝐴}
3		tpssbd.2	. . 3 ⊢ (𝜑 → {𝐴, 𝐵, 𝐶} ⊆ 𝐷)
4	2, 3	eqsstrrid 4003	. 2 ⊢ (𝜑 → {𝐵, 𝐶, 𝐴} ⊆ 𝐷)
5	1, 4	tpssad 32487	1 ⊢ (𝜑 → 𝐵 ∈ 𝐷)

Syntax hints:   → wi 4   ∈ wcel 2107   ⊆ wss 3931  {ctp 4610

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1794  ax-4 1808  ax-5 1909  ax-6 1966  ax-7 2006  ax-8 2109  ax-9 2117  ax-ext 2706

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3or 1087  df-3an 1088  df-tru 1542  df-fal 1552  df-ex 1779  df-sb 2064  df-clab 2713  df-cleq 2726  df-clel 2808  df-ne 2932  df-v 3465  df-dif 3934  df-un 3936  df-ss 3948  df-nul 4314  df-sn 4607  df-pr 4609  df-tp 4611

This theorem is referenced by:  constrlccllem  33733  constrcccllem  33734