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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 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | ci | ⊢ i | |
| 1 | cmul | ⊢ · | |
| 2 | 0 0 1 | co | ⊢ ( i · i ) |
| 3 | caddc | ⊢ + | |
| 4 | c1 | ⊢ 1 | |
| 5 | 2 4 3 | co | ⊢ ( ( i · i ) + 1 ) |
| 6 | cc0 | ⊢ 0 | |
| 7 | 5 6 | wceq | ⊢ ( ( i · i ) + 1 ) = 0 |