Step |
Hyp |
Ref |
Expression |
1 |
|
reixi |
⊢ ( i · i ) = ( 0 −ℝ 1 ) |
2 |
1 1
|
oveq12i |
⊢ ( ( i · i ) · ( i · i ) ) = ( ( 0 −ℝ 1 ) · ( 0 −ℝ 1 ) ) |
3 |
|
1re |
⊢ 1 ∈ ℝ |
4 |
|
rernegcl |
⊢ ( 1 ∈ ℝ → ( 0 −ℝ 1 ) ∈ ℝ ) |
5 |
3 4
|
ax-mp |
⊢ ( 0 −ℝ 1 ) ∈ ℝ |
6 |
|
0re |
⊢ 0 ∈ ℝ |
7 |
|
resubdi |
⊢ ( ( ( 0 −ℝ 1 ) ∈ ℝ ∧ 0 ∈ ℝ ∧ 1 ∈ ℝ ) → ( ( 0 −ℝ 1 ) · ( 0 −ℝ 1 ) ) = ( ( ( 0 −ℝ 1 ) · 0 ) −ℝ ( ( 0 −ℝ 1 ) · 1 ) ) ) |
8 |
5 6 3 7
|
mp3an |
⊢ ( ( 0 −ℝ 1 ) · ( 0 −ℝ 1 ) ) = ( ( ( 0 −ℝ 1 ) · 0 ) −ℝ ( ( 0 −ℝ 1 ) · 1 ) ) |
9 |
|
remul01 |
⊢ ( ( 0 −ℝ 1 ) ∈ ℝ → ( ( 0 −ℝ 1 ) · 0 ) = 0 ) |
10 |
5 9
|
ax-mp |
⊢ ( ( 0 −ℝ 1 ) · 0 ) = 0 |
11 |
|
ax-1rid |
⊢ ( ( 0 −ℝ 1 ) ∈ ℝ → ( ( 0 −ℝ 1 ) · 1 ) = ( 0 −ℝ 1 ) ) |
12 |
5 11
|
ax-mp |
⊢ ( ( 0 −ℝ 1 ) · 1 ) = ( 0 −ℝ 1 ) |
13 |
10 12
|
oveq12i |
⊢ ( ( ( 0 −ℝ 1 ) · 0 ) −ℝ ( ( 0 −ℝ 1 ) · 1 ) ) = ( 0 −ℝ ( 0 −ℝ 1 ) ) |
14 |
|
renegneg |
⊢ ( 1 ∈ ℝ → ( 0 −ℝ ( 0 −ℝ 1 ) ) = 1 ) |
15 |
3 14
|
ax-mp |
⊢ ( 0 −ℝ ( 0 −ℝ 1 ) ) = 1 |
16 |
8 13 15
|
3eqtri |
⊢ ( ( 0 −ℝ 1 ) · ( 0 −ℝ 1 ) ) = 1 |
17 |
2 16
|
eqtri |
⊢ ( ( i · i ) · ( i · i ) ) = 1 |