Metamath Proof Explorer


Definition df-4o

Description: Define the ordinal number 4. (Contributed by Mario Carneiro, 14-Jul-2013)

Ref Expression
Assertion df-4o
|- 4o = suc 3o

Detailed syntax breakdown

Step Hyp Ref Expression
0 c4o
 |-  4o
1 c3o
 |-  3o
2 1 csuc
 |-  suc 3o
3 0 2 wceq
 |-  4o = suc 3o