Definition df-bj-cchat 33120

Description: Define the complex projective line, or Riemann sphere. (Contributed by BJ, 27-Jun-2019.)

Assertion

Ref	Expression
df-bj-cchat	|- CChat = ( CC u. {infty } )

Detailed syntax breakdown of Definition df-bj-cchat

Step	Hyp	Ref	Expression
1		ccchat 33119	. 2 class CChat
2		cc 9934	. . 3 class CC
3		cinfty 33117	. . . 4 class infty
4	3	csn 4177	. . 3 class {infty }
5	2, 4	cun 3572	. 2 class ( CC u. {infty } )
6	1, 5	wceq 1483	1 wff CChat = ( CC u. {infty } )

This definition is referenced by:  bj-rrhatsscchat  33123