Metamath Proof Explorer


Theorem 2cnALT

Description: Alternate proof of 2cn . Shorter but uses more axioms. Similar proofs are possible for 3cn , ... , 9cn . (Contributed by NM, 30-Jul-2004) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Assertion 2cnALT
|- 2 e. CC

Proof

Step Hyp Ref Expression
1 2re
 |-  2 e. RR
2 1 recni
 |-  2 e. CC