Theorem vextru 2805

Description: Every setvar is a member of {𝑥 ∣ ⊤}, which is therefore "a" universal class. Once class extensionality dfcleq 2814 is available, we can say "the" universal class (see df-v 3493). This is sbtru 2071 expressed using class abstractions. (Contributed by BJ, 2-Sep-2023.)

Assertion

Ref	Expression
vextru	⊢ 𝑦 ∈ {𝑥 ∣ ⊤}

Proof of Theorem vextru

Step	Hyp	Ref	Expression
1		tru 1540	. 2 ⊢ ⊤
2	1	vexw 2804	1 ⊢ 𝑦 ∈ {𝑥 ∣ ⊤}

Syntax hints:  ⊤wtru 1537   ∈ wcel 2113  {cab 2798

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795

This theorem depends on definitions:  df-bi 209  df-tru 1539  df-sb 2069  df-clab 2799

This theorem is referenced by:  bj-denoteslem  34209