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	$$⊢4\in ℂ$$

Proof

Step	Hyp	Ref	Expression
1		df-4	$$⊢4=3+1$$
2		3cn	$$⊢3\in ℂ$$
3		ax-1cn	$$⊢1\in ℂ$$
4	2 3	addcli	$$⊢3+1\in ℂ$$
5	1 4	eqeltri	$$⊢4\in ℂ$$