Definition df-4o 6518

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

Assertion

Ref	Expression
df-4o	⊢ 4o = suc 3o

Detailed syntax breakdown of Definition df-4o

Step	Hyp	Ref	Expression
1		c4o 6511	. 2 class 4o
2		c3o 6510	. . 3 class 3o
3	2	csuc 4420	. 2 class suc 3o
4	1, 3	wceq 1373	1 wff 4o = suc 3o

This definition is referenced by:  4on  6527  4onn  6622  hash4  10981