The New Sudoku Players' Forum

[flet]

In row 3, it would seem that I have a triple in columns 2, 8, 9
{37} {137} {137} but simple sudoku gives me an error when I remove the {5} from column 2. Why???

In row 6, columns 7 and 8 form a pair with {14} {14}, but can't do that with {17} {17}. Why???


*-----------------------------------------------------------*
| 1 3457 35 | 69 2 56 | 4579 8 347 |
| 9 457 8 | 3 17 15 | 6 2 147 |
| 6 357 2 | 4 179 8 | 1579 137 137 |
|-------------------+-------------------+-------------------|
| 37 6 13 | 5 34 2 | 8 9 147 |
| 8 9 4 | 1 6 7 | 3 5 2 |
| 357 2 135 | 8 34 9 | 147 147 6 |
|-------------------+-------------------+-------------------|
| 23 13 9 | 7 8 4 | 12 6 5 |
| 245 15 6 | 29 19 13 | 1247 1347 8 |
| 24 8 7 | 26 5 136 | 124 134 9 |
*-----------------------------------------------------------*
[/list]

[wapati]

Thanks Udosuk!

[udosuk]

In row 3, it would seem that I have a triple in columns 2, 8, 9
{37} {137} {137} but simple sudoku gives me an error when I remove the {5} from column 2. Why???

In row 6, columns 7 and 8 form a pair with {14} {14}, but can't do that with {17} {17}. Why???

Code: Select all

 *-----------------------------------------------------------*
 | 1     3457  35    | 69    2     56    | 4579  8     347   |
 | 9     457   8     | 3     17    15    | 6     2     147   |
 | 6     357   2     | 4     179   8     | 1579  137   137   |
 |-------------------+-------------------+-------------------|
 | 37    6     13    | 5     34    2     | 8     9     147   |
 | 8     9     4     | 1     6     7     | 3     5     2     |
 | 357   2     135   | 8     34    9     | 147   147   6     |
 |-------------------+-------------------+-------------------|
 | 23    13    9     | 7     8     4     | 12    6     5     |
 | 245   15    6     | 29    19    13    | 1247  1347  8     |
 | 24    8     7     | 26    5     136   | 124   134   9     |
 *-----------------------------------------------------------*

r3c289 do not form a hidden triple of {137} bacause {17} can appear in other cells on the row, namely r3c57.

Similarly, r6c78 do not form a hidden pair of {14} or {17} because 1,4,7 can appear in other cells on the row...

Look at this page for a proper definition of hidden subsets:

http://www.sudopedia.org/wiki/Hidden_Subset