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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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 Posted: Sat May 11, 2013 2:44 pm Post subject: Free Press May 10, 2013 |
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Not yet started ...
| Code: | Puzzle: FP051013
+-------+-------+-------+
| . . . | . 1 . | . 8 . |
| 6 . . | . . 7 | . . . |
| . 2 5 | 6 . 9 | . . 4 |
+-------+-------+-------+
| 4 . . | . . . | 2 . . |
| 2 . . | 4 3 5 | . . 9 |
| . . 9 | . . . | . . 1 |
+-------+-------+-------+
| 5 . . | 8 . 1 | 7 9 . |
| . . . | 2 . . | . . 3 |
| . 1 . | . 5 . | . . . |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site
Keith |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Sat May 11, 2013 5:27 pm Post subject: |
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after a 462 xy-wing removing a 2 from r2c9 I wound up here:
| Code: | *-----------------------------------------------------------*
| 39 349 7 | 5 1 24 | 69 8 26 |
| 6 489 b48 | 3 24 7 | 19 12 5 |
| 1 2 5 | 6 8 9 | 3 7 4 |
|-------------------+-------------------+-------------------|
| 4 3568 b368 | 1 9 68 | 2 a35 7 |
| 2 7 1 | 4 3 5 | 8 6 9 |
| 38 3568 9 | 7 26 268 |a45 35-4 1 |
|-------------------+-------------------+-------------------|
| 5 346 2346 | 8 46 1 | 7 9 26 |
| 89 4689 b468 | 2 7 46 | 15 15 3 |
| 7 1 c26 | 9 5 3 | 6-4 c24 8 |
*-----------------------------------------------------------*
(4=3)r4c8,r6c7-(3=486)r248c3-(6=4)r9c38 => -4r9c7,r6c8; ste |
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JC Van Hay
Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium
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| Posted: Sat May 11, 2013 6:24 pm Post subject: |
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#1. 18 Singles
| Code: | +------------------+----------------+------------------+
| 39 349 7 | 35 1 4(2) | 569 8 5(26) |
| 6 3489 348 | 35 4-2 7 | 159 125 25 |
| 1 2 5 | 6 8 9 | 3 7 4 |
+------------------+----------------+------------------+
| 4 38(56) 368 | 1 9 68 | 2 35 7 |
| 2 7 1 | 4 3 5 | 8 6 9 |
| 38 38(56) 9 | 7 (26) 68-2 | (45) 345 1 |
+------------------+----------------+------------------+
| 5 34(6) 2346 | 8 4(6) 1 | 7 9 2(6) |
| 89 489(6) 468 | 2 7 4(6) | 1456 145 3 |
| 7 1 246 | 9 5 3 | (46) 24 8 |
+------------------+----------------+------------------+ |
#2. Chain[8] : 2r1c6=(2-6)r1c9=6r7c9-[6r7c2 and 6r7c5=6r8c6-6r8c2 and (6=4)r9c7-(4=5)r6c7-5r6c2=(5-6)r4c2]=6r6c2-(6=2)r6c5 :=> -2r2c5.r6c6; ste
Note : the chain can also be written as a Kraken Column 6C2. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sun May 12, 2013 1:00 am Post subject: |
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This was a tough nut to crack. I used a chain which eliminated 8 from r4c23 and r6c6, leaving me here, where I then needed another chain.
| Code: |
+--------------+----------+------------+
| 39 349 7 | 35 1 24 | 69 8 256 |
| 6 3489 348 | 35 24 7 | 19 12 25 |
| 1 2 5 | 6 8 9 | 3 7 4 |
+--------------+----------+------------+
| 4 356 36 | 1 9 8 | 2 35 7 |
| 2 7 1 | 4 3 5 | 8 6 9 |
| 38 358 9 | 7 26 26 | 45 345 1 |
+--------------+----------+------------+
| 5 346 2346 | 8 46 1 | 7 9 26 |
| 89 4689 468 | 2 7 46 | 15 15 3 |
| 7 1 26 | 9 5 3 | 46 24 8 |
+--------------+----------+------------+
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Play this puzzle online at the Daily Sudoku site
(6=3)r4c3-(3=5)r4c8-(5=1)r8c8-(125=6)r2c89r1c9-r7c9=6r9c7=>r9c3<>6 |
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Leren
Joined: 13 May 2013
Posts: 5
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| Posted: Mon May 13, 2013 10:07 pm Post subject: |
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| Code: | *--------------------------------------------------------------*
| 39 d349 7 | 35 1 c24 | 69 8 h256 |
| 6 3489 348 | 35 b24 7 | 19 12 5-2 |
| 1 2 5 | 6 8 9 | 3 7 4 |
|--------------------+--------------------+--------------------|
| 4 3568 368 | 1 9 68 | 2 35 7 |
| 2 7 1 | 4 3 5 | 8 6 9 |
| 38 3568 9 | 7 26 268 | 45 345 1 |
|--------------------+--------------------+--------------------|
| 5 e36-4 f24-36 | 8 a46 1 | 7 9 g26 |
| 89 4689 468 | 2 7 46 | 15 15 3 |
| 7 1 26 | 9 5 3 | 46 24 8 |
*--------------------------------------------------------------* |
*(4) r7c5 = r2c5 - r1c6 = r1c2 - r7c2 =* (4-2) r7c3 = r7c9 - r1c9 = r1c6 loop => -4 r7c2, -36 r7c3, -2 r2c9; stte
Leren |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sun Jun 02, 2013 1:53 pm Post subject: |
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After basics:
| Code: | +----------------+----------------+----------------+
| 39 *349 7 | 35 1 *24 | 69 8 256 |
| 6 3489 348 | 35 *C24 7 | 19 12 -25 |
| 1 2 5 | 6 8 9 | 3 7 4 |
+----------------+----------------+----------------+
| 4 3568 368 | 1 9 68 | 2 35 7 |
| 2 7 1 | 4 3 5 | 8 6 9 |
| 38 3568 9 | 7 B26 268 | 45 345 1 |
+----------------+----------------+----------------+
| 5 3-4-6 234-6 | 8 *D46 1 | 7 9 A26 |
| 89 4689 468 | 2 7 46 | 15 15 3 |
| 7 1 26 | 9 5 3 | 46 24 8 |
+----------------+----------------+----------------+ |
M-wing: If A is 6 B is 6. Extending 2 to C, R2C9<>2. (This is also an XY-wing ACD.)
M-wing: If A is 2 B is 2. Extending 6 to D, R7C23<>6.
SS on 4 in R1C5. R7C2<>4.
Keith |
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JC Van Hay
Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium
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| Posted: Sun Jun 02, 2013 6:27 pm Post subject: |
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| Leren wrote: | | Code: | *--------------------------------------------------------------*
| 39 d349 7 | 35 1 c24 | 69 8 h256 |
| 6 3489 348 | 35 b24 7 | 19 12 5-2 |
| 1 2 5 | 6 8 9 | 3 7 4 |
|--------------------+--------------------+--------------------|
| 4 3568 368 | 1 9 68 | 2 35 7 |
| 2 7 1 | 4 3 5 | 8 6 9 |
| 38 3568 9 | 7 26 268 | 45 345 1 |
|--------------------+--------------------+--------------------|
| 5 e36-4 f24-36 | 8 a46 1 | 7 9 g26 |
| 89 4689 468 | 2 7 46 | 15 15 3 |
| 7 1 26 | 9 5 3 | 46 24 8 |
*--------------------------------------------------------------* |
*(4) r7c5 = r2c5 - r1c6 = r1c2 - r7c2 =* (4-2) r7c3 = r7c9 - r1c9 = r1c6 loop => -4 r7c2, -36 r7c3, -2 r2c9; stte
Leren |
Hi Leren, I missed your post for some time 
Nice catch ! But ... Your chain as it is written is not an explicit loop and only eliminates 4r7c2 as it contains Kite(4R1C5) :=> -4r7c2!
To get "the loop", the simplest thing to do is to use 4B2 instead of 4C5 as follows :2r7c3=2r7c9-2r1c9=(2-4)r1c6=[4r1c2-4r7c2 and 4r2c5-4r7c5]=4r7c3 @
or, in reverse order,
4r7c3=[4r7c2-4r1c2 or 4r7c5-4r2c5]=(4-2)r1c6=2r1c9-2r7c9=2r7c3 @
:=> -2r2c9,r7c3=24(:=>r7c2=3 ... "->-4r7c2") Note : Only the "true" weak links outside the "brackets" become strong, as the loop only requires the derived SIS 4r1c6=4r7c3.
Regards, JC |
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oaxen
Joined: 10 Jul 2006
Posts: 96
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| Posted: Mon Jun 03, 2013 9:22 am Post subject: |
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| Of all the available bivalues, 2 in column 8 seems to be most interesting. A quick check gives 8 must-bees independent of which one of the 2īs. one chooses |
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aran
Joined: 19 Apr 2010
Posts: 70
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| Posted: Mon Jun 03, 2013 12:38 pm Post subject: |
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JC Van Hay
Or thinking in base/cover/rank terms
it's a rank 1 structure => not a loop
ie
Base
4 truths : 2r7 2r1 4r1 4r7
Cover :
5 truths : 2c9 r1c6 4c2 r7c3 + 4r7c5
Rank = 5-4=1.
Logic then becomes :
4r7c5 false =>rank 0 =>loop =><2>r2c9 <4>r18c2 <36>r7c3
4r7c5 true => -(4=2)r2c5-2r1c6=2r1c9 =><2>r2c9 (2-36)r7c3
Hence what is common is eliminated : <2>r2c9 <36>r7c3 |
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JC Van Hay
Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium
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| Posted: Mon Jun 03, 2013 7:01 pm Post subject: |
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Aran
Nice interpretation while using non-overlapping truths!
On my side, I may be improperly called loops the chains I wrote all the more since their ranks are undefined due to overlapping truths.
Nonetheless, the rank 0 links were clearly identified which is not so easy in the more general cases !
And I don't speak, as you know, of the different needed "chains" to explain each group of eliminations ! |
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aran
Joined: 19 Apr 2010
Posts: 70
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| Posted: Thu Jun 06, 2013 10:44 am Post subject: |
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| JC Van Hay wrote: | Aran
On my side, I may be improperly called loops the chains I wrote all the more since their ranks are undefined due to overlapping truths.
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Insofar as it has the form x=.......=y-x it's a loop
Insofar as it has rank 1, it's not a loop...
Au choix !
Just out of interest, xx to uniqueness
| Code: |
*-----------------------------------------------------------*
| 39 349 7 | 35 1 24 | 69 8 256 |
| 6 3489 348 | 35 24 7 | 19 12 25 |
| 1 2 5 | 6 8 9 | 3 7 4 |
|-------------------+-------------------+-------------------|
| 4 3568 368 | 1 9 68 | 2 35 7 |
| 2 7 1 | 4 3 5 | 8 6 9 |
| 38 3568 9 | 7 26 268 | 45 345 1 |
|-------------------+-------------------+-------------------|
| 5 346 2346 | 8 46 1 | 7 9 26 |
| 89 4689 468 | 2 7 46 | 15 15 3 |
| 7 1 26 | 9 5 3 | 46 24 8 |
*-----------------------------------------------------------* |
UR48r28c23 = sis {4r2c5 4r8c6 89r8c12}
DP893r816c12 = sis {4r1c2 56r6c2}
=>UR48 = sis {4r2c5 4r8c6 4r1c2 56r6c2}
4r2c5 4r8c6 4r1c2 =>r1c6=2
6r6c2-(6=2)r6c5-r2c5=2r1c6
5r6c2-(5=4)r6c7-(4=6)r9c7-r1c7=(6-2)r1c9=2r1c6
=>r1c6=2 ste |
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