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Conjugate-Linked ALS's plus Extended Purple Cow Example

 
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Bud



Joined: 06 May 2010
Posts: 47
Location: Tampa, Florida

PostPosted: Tue Jun 21, 2011 11:42 pm    Post subject: Conjugate-Linked ALS's plus Extended Purple Cow Example Reply with quote

000400150001095040005012030009000004000526000800000600070100400000050700013008000

After making basic moves the puzzle is as shown in the diagram. At this point I look for the most powerful advanced move I can find and at least temporarily ignore weaker advanced moves. In this case it is the conjugate linked ALSís in box456. The logic is as follows. If conjugate C=3, ALS A=1278 or else if D=3, ALS B=1247. In either case r4c1<>127, r4c2<>2,and r6c89<>2. This also makes r5c1=1.

Code:

+----------------------+-------------------+-------------------+
| 23679    23689  2678 | 4     3678  37    | 1    5      26789 |
| 2367     2368   1    | 3678  9     5     | 28   4      2678  |
| 4679     4689   5    | 678   1     2     | 89   3      6789  |
+----------------------+-------------------+-------------------+
|-1-236-7 -2356   9    | 378A  378A  137A  | 235C  127A  4     |
| 1347B    34B    47B  | 5     2     6     | 389D 1789   189   |
| 8        235    27B  | 379   347   13479 | 6    1-27   1-25  |
+----------------------+-------------------+-------------------+
| 2569     7      268  | 1     36    39    | 4    2689   23589 |
| 2469     24689  2468 | 2369  5     349   | 7    12689  12389 |
| 24569    1      3    | 2679  467   8     | 259  269    259   |
+----------------------+-------------------+-------------------+


After applying the conjugate ALSís move, the puzzle is as shown in the diagram below. The cells in the purple cow pattern are denoted by *. The extension cell is denoted by ^. Note that the basic pattern consists of a single digit(4) 4-cell AIC and a single digit(7) 3-cell chain with (at least?) one strong link (in column 3). The ends of these two chains are connected together(r5c3 and r6c6). Note that in this case the 4-cell AIC is a useless skyscraper pattern. It could also be any type of useful or useless turbot fish pattern , although in most other purple cows I have found, the 4-cell AIC is not a Turbot fish. Purple cow logic is as follows. One or both ends of the 4-cell AIC must be 4. Either (4)r5c3=(7)r6c3=(1)r6c8 or (4)r6c6. In either case r6c6<>17. This also makes r4c6=1 and r1c6=7.

Code:

+--------------------+--------------------+-------------------+
| 23679  23689  268  | 4     3678   37    | 1    5      26789 |
| 2367   2368   1    | 3678  9      5     | 28   4      2678  |
| 4679   4689   5    | 678   1      2     | 89   3      6789  |
+--------------------+--------------------+-------------------+
| 36     356    9    | 378   378    137   | 235  127    4     |
| 1      34     47*  | 5     2      6     | 389  789    89    |
| 8      235    27*  | 379   347  -134-79*| 6    17^    15    |
+--------------------+--------------------+-------------------+
| 2569   7      268  | 1     36     39    | 4    2689   23589 |
| 2469   24689  2468*| 2369  5      349*  | 7    12689  12389 |
| 24569  1      3    | 2679  467    8     | 259  269    259   |
+--------------------+--------------------+-------------------+


The purple cow has much in common with the S-Wing. Both are basic 2-digit, 5-cell patterns which can be extended to get additional cell eliminations. Both patterns are discontinuous NLís which can become 3-digit continuous loops. These continuous loops occur much more often in the S-Wing pattern than in the purple cow pattern. I have several examples of the former but only two of the latter. I have been able to get 4 digit eliminations with an extended S-Wing but only 2 for the extended purple cow. From my experience the purple cow is the least common of the 4 2-digit 4 and 5-cell patterns, but it is not rare.
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