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storm_norm
Joined: 18 Oct 2007 Posts: 1741
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Posted: Sat Apr 16, 2011 5:28 pm Post subject: Daily Sudoku Competition for Apr 15 |
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200010809008009000950020000040000060600007904010000050000080012000600000403090008
Code: |
+-------+-------+-------+
| 2 . . | . 1 . | 8 . 9 |
| . . 8 | . . 9 | . . . |
| 9 5 . | . 2 . | . . . |
+-------+-------+-------+
| . 4 . | . . . | . 6 . |
| 6 . . | . . 7 | 9 . 4 |
| . 1 . | . . . | . 5 . |
+-------+-------+-------+
| . . . | . 8 . | . 1 2 |
| . . . | 6 . . | . . . |
| 4 . 3 | . 9 . | . . 8 |
+-------+-------+-------+
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Sun Apr 17, 2011 1:59 pm Post subject: |
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I previously posted a solution only later to realize that I had made an error in basics; somehow I had r8c5=7.
In any case, I finally got around to working the puzzle again and found this one step solution.....
anp(57=1)r78c1-(1=3)r2c1-als(3=67)r12c2-(6)r9c2=(6)r7c3; r7c3<>57=6
Ted
Last edited by tlanglet on Mon Apr 18, 2011 2:31 pm; edited 1 time in total |
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peterj
Joined: 26 Mar 2010 Posts: 974 Location: London, UK
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Posted: Sun Apr 17, 2011 2:25 pm Post subject: |
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One step... and a fun example of how a hidden-set interpretation makes a chain appear shorter but makes your head hurt (at least mine!)
Quote: | (6)r7c2=hp(26)r9c2|r8c3 - (1)r8c3=hp(14)r13c2 ; r13c2<>6 |
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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Sun Apr 17, 2011 11:29 pm Post subject: |
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Peter,
Is your solution to this puzzle ... or the one Norm withdrew? |
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peterj
Joined: 26 Mar 2010 Posts: 974 Location: London, UK
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Posted: Mon Apr 18, 2011 6:48 am Post subject: |
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daj95376 wrote: | Is your solution to this puzzle ... or the one Norm withdrew? |
It's a solution to the puzzle in the first post - I think. Though it looks even more opaque this morning... |
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keith
Joined: 19 Sep 2005 Posts: 3355 Location: near Detroit, Michigan, USA
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Posted: Mon Apr 18, 2011 10:31 am Post subject: |
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After basics: Code: | +----------------+----------------+----------------+
| 2 367 46 | 357 1 356 | 8 34 9 |
| 13 367 8 | 347 467 9 | 157 2 1567 |
| 9 5 146 | 378 2 368 | 17 34 167 |
+----------------+----------------+----------------+
| 3578 4 579 | 289 35 28 | 1237 6 137 |
| 6 23 25 | 1 35 7 | 9 8 4 |
| 378 1 79 | 2489 46 2468 | 237 5 37 |
+----------------+----------------+----------------+
| 57 9 567 | 3457 8 345 | 3456 1 2 |
| 157 8 1257 | 6 47 2345 | 345 9 35 |
| 4 26 3 | 25 9 1 | 56 7 8 |
+----------------+----------------+----------------+ | Keith |
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Asellus
Joined: 05 Jun 2007 Posts: 865 Location: Sonoma County, CA, USA
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Posted: Tue Apr 19, 2011 2:58 am Post subject: |
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A little coloring led quickly to:
(3=1)r2c1 - (1)r8c1=(1-2)r8c3=(2)r9c2 - (2=3)r5c2; r12c2|r46c1<>3 |
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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Tue Apr 19, 2011 3:25 am Post subject: |
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Asellus wrote: | A little coloring led quickly to:
(3=1)r2c1 - (1)r8c1=(1-2)r8c3=(2)r9c2 - (2=3)r5c2; r12c2|r46c1<>3 |
Although Asellus's chain is short and correct, it fails to show a secondary property that often accompanies this pattern ... and always catches my attention. The weak inference on <1> in [c1] is founded on a strong link. Similarly for the weak inference on <2> in [c2]. Maybe this is what Asellus meant by "a little coloring". These strong links caught his attention as well, maybe. |
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Asellus
Joined: 05 Jun 2007 Posts: 865 Location: Sonoma County, CA, USA
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Posted: Tue Apr 19, 2011 3:13 pm Post subject: |
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daj95376 wrote: | Maybe this is what Asellus meant by "a little coloring". These strong links caught his attention as well, maybe. |
Actually, I meant coloring, starting with <2>s:
Code: | +-----------------+-----------------+----------------+
| 2 367 46 | 357 1 356 | 8 34 9 |
| 13 367 8 | 347 467 9 | 157 2 1567 |
| 9 5 146 | 378 2 368 | 17 34 167 |
+-----------------+-----------------+----------------+
| 3578 4 579 | 289 35 28 | 1237 6 137 |
| 6 2A3a 2a5A | 1 35 7 | 9 8 4 |
| 378 1 79 | 2489 46 2468 | 237 5 37 |
+-----------------+-----------------+----------------+
| 57 9 567 | 3457 8 345 | 3456 1 2 |
| 157 8 12A57 | 6 47 2a345 | 345 9 35 |
| 4 2a6A 3 | 25 9 1 | 56 7 8 |
+-----------------+-----------------+----------------+ |
The conjugate pair I then noticed was that of the <1>s in b7. I could have started multi-coloring with them, but noted simply that "A" color could be transported to 1A in r8c1 and thence to 3A in r2c1, providing the <3> pincers. All that remained was to write down the AIC.
You will pretty much not find me using the term "strong link" any longer. I find it too easily confused with strong inference, thus getting in the way of understanding. I prefer to refer to conjugate pairs. It is easier to state that conjugate pairs possess both weak and strong inferences without the language getting in the way. |
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ronk
Joined: 07 May 2006 Posts: 398
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Posted: Tue Apr 19, 2011 5:34 pm Post subject: |
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Asellus wrote: | The conjugate pair I then noticed was that of the <1>s in b7. I could have started multi-coloring with them, but noted simply that "A" color could be transported to 1A in r8c1 and thence to 3A in r2c1, providing the <3> pincers. All that remained was to write down the AIC. |
It is multi-coloring for the overall AIC, so I find these statements confusing. IOW r8c3 might ultimately be neither <2> nor <1>.
Asellus wrote: | You will pretty much not find me using the term "strong link" any longer. I find it too easily confused with strong inference, thus getting in the way of understanding. I prefer to refer to conjugate pairs. |
That's a very good practice. |
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Asellus
Joined: 05 Jun 2007 Posts: 865 Location: Sonoma County, CA, USA
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Posted: Wed Apr 20, 2011 9:43 am Post subject: |
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ronk wrote: | It is multi-coloring for the overall AIC, so I find these statements confusing. IOW r8c3 might ultimately be neither <2> nor <1>. |
Yes, of course. (Or better, r8c3 cannot be BOTH <2> and <1>.) As noted, it can be considered as multi-coloring. However, once I have a color cluster I often look for short sequences of alternating inferences extending from the cluster. These often replicate simple multi-coloring, but not always. For instance, coloring does not accommodate the strong inferences of ALS or ER very readily. In any case, it is analogous to pincer or fin transport and, like those, done without any color marking. The transported "colors" are ephemeral and not marked. It is in effect a shorthand for keeping track of the propagated strong inferences. But so, too, is pincer transport. |
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ronk
Joined: 07 May 2006 Posts: 398
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Posted: Wed Apr 20, 2011 3:53 pm Post subject: |
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Asellus wrote: | The transported "colors" are ephemeral and not marked. It is in effect a shorthand for keeping track of the propagated strong inferences. But so, too, is pincer transport. |
OK, I understand now, thanks. |
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