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 ( 𝑁𝑉 → Pred ( 𝑅 , 𝐴 , 𝑁 ) = [ 𝑁 ] ( 𝑅𝐴 ) )

Proof

Step Hyp Ref Expression
1 dfpred3g ( 𝑁𝑉 → Pred ( 𝑅 , 𝐴 , 𝑁 ) = { 𝑚𝐴𝑚 𝑅 𝑁 } )
2 ec1cnvres ( 𝑁𝑉 → [ 𝑁 ] ( 𝑅𝐴 ) = { 𝑚𝐴𝑚 𝑅 𝑁 } )
3 1 2 eqtr4d ( 𝑁𝑉 → Pred ( 𝑅 , 𝐴 , 𝑁 ) = [ 𝑁 ] ( 𝑅𝐴 ) )