Definition df-3o 6662

Description: Define the ordinal number 3. (Contributed by Mario Carneiro, 14-Jul-2013.)

Assertion

Ref	Expression
df-3o	⊢ 3o = suc 2o

Detailed syntax breakdown of Definition df-3o

Step	Hyp	Ref	Expression
1		c3o 6655	. 2 class 3o
2		c2o 6654	. . 3 class 2o
3	2	csuc 4491	. 2 class suc 2o
4	1, 3	wceq 1398	1 wff 3o = suc 2o

This definition is referenced by:  3on  6671  3onn  6768  pw1ne3  7553  pw1nel3  7554  sucpw1nel3  7556  3nelsucpw1  7557  3nsssucpw1  7559  onntri35  7560  hash3  11203  3dom  16874