Metamath Proof Explorer


Theorem predonOLD

Description: Obsolete version of predon as of 16-Oct-2024. (Contributed by Scott Fenton, 27-Mar-2011) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Assertion predonOLD A On Pred E On A = A

Proof

Step Hyp Ref Expression
1 predep A On Pred E On A = On A
2 onss A On A On
3 sseqin2 A On On A = A
4 2 3 sylib A On On A = A
5 1 4 eqtrd A On Pred E On A = A