Metamath Proof Explorer


Axiom ax-i2m1

Description: i-squared equals -1 (expressed as i-squared plus 1 is 0). Axiom 12 of 22 for real and complex numbers, justified by theorem axi2m1 . (Contributed by NM, 29-Jan-1995)

Ref Expression
Assertion ax-i2m1 i i + 1 = 0

Detailed syntax breakdown

Step Hyp Ref Expression
0 ci class i
1 cmul class ×
2 0 0 1 co class i i
3 caddc class +
4 c1 class 1
5 2 4 3 co class i i + 1
6 cc0 class 0
7 5 6 wceq wff i i + 1 = 0