| Step | Hyp | Ref | Expression |
| 1 |
|
eqtr3 |
(a -ZN 0) *Z (b -ZN 0) = b0 a *Z b0 b -> (a -ZN 0) *Z (b -ZN 0) = b0 (a * b) -> b0 a *Z b0 b = b0 (a * b) |
| 2 |
|
zmuleq |
a -ZN 0 = b0 a -> b -ZN 0 = b0 b -> (a -ZN 0) *Z (b -ZN 0) = b0 a *Z b0 b |
| 3 |
|
znsub02 |
a -ZN 0 = b0 a |
| 4 |
2, 3 |
ax_mp |
b -ZN 0 = b0 b -> (a -ZN 0) *Z (b -ZN 0) = b0 a *Z b0 b |
| 5 |
|
znsub02 |
b -ZN 0 = b0 b |
| 6 |
4, 5 |
ax_mp |
(a -ZN 0) *Z (b -ZN 0) = b0 a *Z b0 b |
| 7 |
1, 6 |
ax_mp |
(a -ZN 0) *Z (b -ZN 0) = b0 (a * b) -> b0 a *Z b0 b = b0 (a * b) |
| 8 |
|
eqtr4 |
(a -ZN 0) *Z (b -ZN 0) = a * b + 0 * 0 -ZN (a * 0 + b * 0) -> b0 (a * b) = a * b + 0 * 0 -ZN (a * 0 + b * 0) -> (a -ZN 0) *Z (b -ZN 0) = b0 (a * b) |
| 9 |
|
zmulzn |
(a -ZN 0) *Z (b -ZN 0) = a * b + 0 * 0 -ZN (a * 0 + b * 0) |
| 10 |
8, 9 |
ax_mp |
b0 (a * b) = a * b + 0 * 0 -ZN (a * 0 + b * 0) -> (a -ZN 0) *Z (b -ZN 0) = b0 (a * b) |
| 11 |
|
eqtr3 |
a * b -ZN 0 = b0 (a * b) -> a * b -ZN 0 = a * b + 0 * 0 -ZN (a * 0 + b * 0) -> b0 (a * b) = a * b + 0 * 0 -ZN (a * 0 + b * 0) |
| 12 |
|
znsub02 |
a * b -ZN 0 = b0 (a * b) |
| 13 |
11, 12 |
ax_mp |
a * b -ZN 0 = a * b + 0 * 0 -ZN (a * 0 + b * 0) -> b0 (a * b) = a * b + 0 * 0 -ZN (a * 0 + b * 0) |
| 14 |
|
znsubeq |
a * b = a * b + 0 * 0 -> 0 = a * 0 + b * 0 -> a * b -ZN 0 = a * b + 0 * 0 -ZN (a * 0 + b * 0) |
| 15 |
|
eqtr2 |
a * b + 0 * 0 = a * b + 0 -> a * b + 0 = a * b -> a * b = a * b + 0 * 0 |
| 16 |
|
addeq2 |
0 * 0 = 0 -> a * b + 0 * 0 = a * b + 0 |
| 17 |
|
mul0 |
0 * 0 = 0 |
| 18 |
16, 17 |
ax_mp |
a * b + 0 * 0 = a * b + 0 |
| 19 |
15, 18 |
ax_mp |
a * b + 0 = a * b -> a * b = a * b + 0 * 0 |
| 20 |
|
add0 |
a * b + 0 = a * b |
| 21 |
19, 20 |
ax_mp |
a * b = a * b + 0 * 0 |
| 22 |
14, 21 |
ax_mp |
0 = a * 0 + b * 0 -> a * b -ZN 0 = a * b + 0 * 0 -ZN (a * 0 + b * 0) |
| 23 |
|
eqtr2 |
a * 0 + b * 0 = 0 + 0 -> 0 + 0 = 0 -> 0 = a * 0 + b * 0 |
| 24 |
|
addeq |
a * 0 = 0 -> b * 0 = 0 -> a * 0 + b * 0 = 0 + 0 |
| 25 |
|
mul0 |
a * 0 = 0 |
| 26 |
24, 25 |
ax_mp |
b * 0 = 0 -> a * 0 + b * 0 = 0 + 0 |
| 27 |
|
mul0 |
b * 0 = 0 |
| 28 |
26, 27 |
ax_mp |
a * 0 + b * 0 = 0 + 0 |
| 29 |
23, 28 |
ax_mp |
0 + 0 = 0 -> 0 = a * 0 + b * 0 |
| 30 |
|
add0 |
0 + 0 = 0 |
| 31 |
29, 30 |
ax_mp |
0 = a * 0 + b * 0 |
| 32 |
22, 31 |
ax_mp |
a * b -ZN 0 = a * b + 0 * 0 -ZN (a * 0 + b * 0) |
| 33 |
13, 32 |
ax_mp |
b0 (a * b) = a * b + 0 * 0 -ZN (a * 0 + b * 0) |
| 34 |
10, 33 |
ax_mp |
(a -ZN 0) *Z (b -ZN 0) = b0 (a * b) |
| 35 |
7, 34 |
ax_mp |
b0 a *Z b0 b = b0 (a * b) |