The New Sudoku Players' Forum

[domp]

hi Leren,
................12..3.45..6.3..67..86..8..3..8..9......5.4...3..7....2..3...78..5;332431;dob;12_12_03;D;2;r7c1 r8c1 r3c2 r4c3 1249;r5c2 r6c2 r3c1 r9c3 1249;
It's a Dobrichev puzzle, and the double exocet parameters are written.

My solver recognise this double exocet with the same parameters, and with 3 cover house column 4.7.8, but with ONE error in cover house : 4 r1c7, and eliminates 36 other candidates. It looks that all '4' are eliminated in the upper right box !
May I add a test to check if such pattern is present, before cover house eliminations proceeding ?
I don't find any web comment about such mistake.

dominique

[Leren]

Code: Select all

*--------------------------------------------------------------*
| 124579 M12489-6  124569  | 1267 1289 1269 | 45789 45789 3    |
| 4579   M4689-6   4569    | 367  389  369  | 45789 1     2    |
| 1279   T129-8    3       | 127  4    5    | 789   789   6    |
|--------------------------+----------------+------------------|
| 12459   3       T1249-5  | 125  6    7    | 1459  2459  8    |
| 6       1249    M1279-45 | 8    125  124  | 3     24579 1479 |
| 8       124     M127-45  | 9    1235 1234 | 14567 24567 147  |
|--------------------------+----------------+------------------|
|B129     5        12689   | 4    129  1269 | 16789 3     179  |
| 149     7        14689   | 1356 1359 1369 | 2     4689  149  |
| 3       12469    12469   | 126  7    8    | 1469  469   5    |
*--------------------------------------------------------------*

Exocet 1: r7c1 r8c1 r3c2 r4c3 1249 => - 8 r3c2, - 5 r4c3, - 6 r12c2, - 45 r56c3, lclste

That was my Exocet solution for this puzzle. There are two issues of controversy here.

1. Despite 4 failing the S cell cover set test it must be possible to prove that if 4 is in a base cell it must be in at least one target cell. So it is not a J Exocet, but is an Exocet in the more general sense.

I call this a full digit expansion of the relevant digit, and there is some controversy as to how far you should go in proving this.

2. The puzzle was probably included in a list of Double Exocet puzzles before the full implications of Mirror Node eliminations were known.

As I have shown, the puzzle does not actually need the second Exocet to be solved, but if you prefer to look for Double Exocets before you consider Mirror Node eliminations, then that is fine by me.

Leren