Theorem bnj213

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

	Ref	Expression
Assertion	bnj213	⊢ pred ( 𝑋 , 𝐴 , 𝑅 ) ⊆ 𝐴

Proof

Step	Hyp	Ref	Expression
1		df-bnj14	⊢ pred ( 𝑋 , 𝐴 , 𝑅 ) = { 𝑦 ∈ 𝐴 ∣ 𝑦 𝑅 𝑋 }
2	1	ssrab3	⊢ pred ( 𝑋 , 𝐴 , 𝑅 ) ⊆ 𝐴