Definition df-3o 6648

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 6641	. 2 class 3o
2		c2o 6640	. . 3 class 2o
3	2	csuc 4485	. 2 class suc 2o
4	1, 3	wceq 1398	1 wff 3o = suc 2o

This definition is referenced by:  3on  6657  3onn  6754  pw1ne3  7539  pw1nel3  7540  sucpw1nel3  7542  3nelsucpw1  7543  3nsssucpw1  7545  onntri35  7546  hash3  11176  3dom  16754