Theorem vexwt 2803

Description: A standard theorem of predicate calculus (stdpc4 2072) expressed using class abstractions. Closed form of vexw 2804. (Contributed by BJ, 14-Jun-2019.)

Assertion

Ref	Expression
vexwt	⊢ (∀𝑥𝜑 → 𝑦 ∈ {𝑥 ∣ 𝜑})

Proof of Theorem vexwt

Step	Hyp	Ref	Expression
1		stdpc4 2072	. 2 ⊢ (∀𝑥𝜑 → [𝑦 / 𝑥]𝜑)
2		df-clab 2799	. 2 ⊢ (𝑦 ∈ {𝑥 ∣ 𝜑} ↔ [𝑦 / 𝑥]𝜑)
3	1, 2	sylibr 236	1 ⊢ (∀𝑥𝜑 → 𝑦 ∈ {𝑥 ∣ 𝜑})

Syntax hints:   → wi 4  ∀wal 1534  [wsb 2068   ∈ 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  ax-4 1809  ax-5 1910

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

This theorem is referenced by:  bj-issetwt  34211  bj-abv  34245