Metamath Proof Explorer


Theorem axicn

Description: _i is a complex number. Axiom 3 of 22 for real and complex numbers, derived from ZF set theory. This construction-dependent theorem should not be referenced directly; instead, use ax-icn . (Contributed by NM, 23-Feb-1996) (New usage is discouraged.)

Ref Expression
Assertion axicn
|- _i e. CC

Proof

Step Hyp Ref Expression
1 0r
 |-  0R e. R.
2 1sr
 |-  1R e. R.
3 df-i
 |-  _i = <. 0R , 1R >.
4 3 eleq1i
 |-  ( _i e. CC <-> <. 0R , 1R >. e. CC )
5 opelcn
 |-  ( <. 0R , 1R >. e. CC <-> ( 0R e. R. /\ 1R e. R. ) )
6 4 5 bitri
 |-  ( _i e. CC <-> ( 0R e. R. /\ 1R e. R. ) )
7 1 2 6 mpbir2an
 |-  _i e. CC