Theorem bnj21 30037

Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011.) (New usage is discouraged.)

Hypothesis

Ref	Expression
bnj21.1	⊢ 𝐵 = {𝑥 ∈ 𝐴 ∣ 𝜑}

Assertion

Ref	Expression
bnj21	⊢ 𝐵 ⊆ 𝐴

Distinct variable group:   𝑥,𝐴

Allowed substitution hints:   𝜑(𝑥)   𝐵(𝑥)

Proof of Theorem bnj21

Step	Hyp	Ref	Expression
1		bnj21.1	. 2 ⊢ 𝐵 = {𝑥 ∈ 𝐴 ∣ 𝜑}
2		ssrab2 3650	. 2 ⊢ {𝑥 ∈ 𝐴 ∣ 𝜑} ⊆ 𝐴
3	1, 2	eqsstri 3598	1 ⊢ 𝐵 ⊆ 𝐴

Syntax hints:   = wceq 1475  {crab 2900   ⊆ wss 3540

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-6 1875  ax-7 1922  ax-10 2006  ax-11 2021  ax-12 2034  ax-13 2234  ax-ext 2590

This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  df-tru 1478  df-ex 1696  df-nf 1701  df-sb 1868  df-clab 2597  df-cleq 2603  df-clel 2606  df-nfc 2740  df-rab 2905  df-in 3547  df-ss 3554

This theorem is referenced by:  bnj1212  30124  bnj213  30206  bnj1286  30341  bnj1312  30380  bnj1523  30393