Definition df-nc 6101

Description: Define the cardinality operation. This is the unique cardinal number containing a given set. Definition from [Rosser] p. 371. (Contributed by Scott Fenton, 24-Feb-2015.)

Assertion

Ref	Expression
df-nc	⊢ Nc A = [A] ≈

Detailed syntax breakdown of Definition df-nc

Step	Hyp	Ref	Expression
1		cA	. . 3 class A
2	1	cnc 6091	. 2 class Nc A
3		cen 6028	. . 3 class ≈
4	1, 3	cec 5945	. 2 class [A] ≈
5	2, 4	wceq 1642	1 wff Nc A = [A] ≈

This definition is referenced by:  nceq  6108  ncex  6117  elncs  6119  ncidg  6122  ncprc  6124  elnc  6125  eqncg  6126  ncseqnc  6128  mucnc  6131  df0c2  6137  1cnc  6139  ncdisjeq  6148