Metamath Proof Explorer


Theorem dfpred4

Description: Alternate definition of the predecessor class when N is a set. (Contributed by Peter Mazsa, 26-Jan-2026)

Ref Expression
Assertion dfpred4 ( 𝑁 ∈ 𝑉 → Pred ( 𝑅 , 𝐴 , 𝑁 ) = [ 𝑁 ] ◡ ( 𝑅 ↾ 𝐴 ) )

Proof

Step Hyp Ref Expression
1 dfpred3g ⊢ ( 𝑁 ∈ 𝑉 → Pred ( 𝑅 , 𝐴 , 𝑁 ) = { 𝑚 ∈ 𝐴 ∣ 𝑚 𝑅 𝑁 } )
2 ec1cnvres ⊢ ( 𝑁 ∈ 𝑉 → [ 𝑁 ] ◡ ( 𝑅 ↾ 𝐴 ) = { 𝑚 ∈ 𝐴 ∣ 𝑚 𝑅 𝑁 } )
3 1 2 eqtr4d ⊢ ( 𝑁 ∈ 𝑉 → Pred ( 𝑅 , 𝐴 , 𝑁 ) = [ 𝑁 ] ◡ ( 𝑅 ↾ 𝐴 ) )