Metamath Proof Explorer


Theorem 2cn

Description: The number 2 is a complex number. (Contributed by NM, 30-Jul-2004) Reduce dependencies on axioms. (Revised by Steven Nguyen, 4-Oct-2022)

Ref Expression
Assertion 2cn 2

Proof

Step Hyp Ref Expression
1 df-2 2 = 1 + 1
2 ax-1cn 1
3 2 2 addcli 1 + 1
4 1 3 eqeltri 2