Theorem 4cn

Description: The number 4 is a complex number. (Contributed by David A. Wheeler, 7-Jul-2016) Reduce dependencies on axioms. (Revised by Steven Nguyen, 4-Oct-2022)

	Ref	Expression
Assertion	4cn	|- 4 e. CC

Proof

Step	Hyp	Ref	Expression
1		df-4	|- 4 = ( 3 + 1 )
2		3cn	|- 3 e. CC
3		ax-1cn	|- 1 e. CC
4	2 3	addcli	|- ( 3 + 1 ) e. CC
5	1 4	eqeltri	|- 4 e. CC