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Clement
Joined: 24 Apr 2006
Posts: 1110
Location: Dar es Salaam Tanzania
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 Posted: Wed May 12, 2010 10:09 pm Post subject: May 13 VH |
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| XY-Wing 48 24 28 eliminating 8 in r4c9 solves the puzzle. |
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prakash
Joined: 02 Jan 2008
Posts: 67
Location: New Jersey, USA
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| Posted: Thu May 13, 2010 12:56 am Post subject: |
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| Goging by how much the puzzle got filled with just the basics, I thought I must have done something wrong. Then came the 248 xy wing at r5c7. Looking for a second opinion before I start the puzzle all over again. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Thu May 13, 2010 2:43 am Post subject: |
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| prakash wrote: | | Goging by how much the puzzle got filled with just the basics, I thought I must have done something wrong. Then came the 248 xy wing at r5c7. Looking for a second opinion before I start the puzzle all over again. |
I agree, much of the puzzle was solved with basics only. There were a number of different techniques that could subsequently be used as one-step solutions. |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Thu May 13, 2010 6:15 am Post subject: |
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Newly named today! 
Baphomet!
| Code: | *--------------------------------------------------*
| 2 6 8 | 5 3 1 | 7 9 4 |
| 3 4 1 | 6 7 9 | 28 28 5 |
| 9 5 7 | 48 2 48 | 3 6 1 |
|----------------+----------------+----------------|
| 6 1 3 |*48 5 7 | 9 248 *28 |
| 5 7 9 | 2 4+8 3 | 48 1 6 |
| 4 8 2 | 1 9 6 | 5 7 3 |
|----------------+----------------+----------------|
| 8 3 6 | 9 1 25 | 24 245 7 |
| 7 2 4 | 3 6 58 | 1 58 9 |
| 1 9 5 | 7 *48 248 | 6 3 *28 |
*--------------------------------------------------*
(8)r4c4-r4c9=r9c9-r9c5; r5c5=8
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Thu May 13, 2010 7:32 am Post subject: |
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Indeed lots of basics
And for us luddites who are happy to stick to the 'old ways'
multicolour wrap(8)
(Or to be elaborate a finned swordfish(8) r459c469, fin r8c6, r9c5<>8!) |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Thu May 13, 2010 8:05 am Post subject: |
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| peterj wrote: |
And for us luddites who are happy to stick to the 'old ways'
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Beware that man he protesteth too much !  |
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George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
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| Posted: Thu May 13, 2010 8:07 am Post subject: yet another route |
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| W Wing :- 28s in boxes 3and 9 operating on 2s in col 7 |
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Thu May 13, 2010 1:27 pm Post subject: |
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| Mogulmeister wrote: | | peterj wrote: |
And for us luddites who are happy to stick to the 'old ways'
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Beware that man he protesteth too much ! |
Yes just envious of discovering a new 'named' sudoku pattern!
It is amazing how much discussion there is on what things are called, fins, almosts, baphomets, anp/ahp etc.etc  |
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George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
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| Posted: Thu May 13, 2010 2:07 pm Post subject: Baphonet and W Wing |
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| This example of a "Baphomet" might as easily been called a W wing with 48s acting on 8s in col 9 denying the same 4 as the Baphomet |
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ronk
Joined: 07 May 2006
Posts: 398
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| Posted: Thu May 13, 2010 2:26 pm Post subject: |
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| arkietech wrote: | Newly named today!
Baphomet!
(8)r4c4-r4c9=r9c9-r9c5
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Since the AIC as written isn't useful, the name 'Baphomet' seems approprate. |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Thu May 13, 2010 2:52 pm Post subject: |
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| ronk wrote: | | Since the AIC as written isn't useful, the name 'Baphomet' seems approprate. |
Help me understand why it is not useful.
Would this be better?
(8)r5c5=r4c4-r4c9=r9c9-r9c5=r5c5; r5c5=8 |
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ronk
Joined: 07 May 2006
Posts: 398
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| Posted: Thu May 13, 2010 3:14 pm Post subject: |
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| arkietech wrote: | | ronk wrote: | | Since the AIC as written isn't useful, the name 'Baphomet' seems approprate. |
Help me understand why it is not useful.
Would this be better?
(8)r5c5=r4c4-r4c9=r9c9-r9c5=r5c5; r5c5=8 |
Much! Weak inferences are 'everywhere' and can be omitted from the ends of an AIC ... because one can validly assume they exist. Not so for strong inferences. |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Thu May 13, 2010 3:21 pm Post subject: |
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| ronk wrote: | | Much! Weak inferences are 'everywhere' and can be omitted from the ends of an AIC ... because one can validly assume they exist. Not so for strong inferences. |
Thanks.
This particular form is very common and most useful in solving puzzles. It needs a name. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Thu May 13, 2010 3:34 pm Post subject: |
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| In addition to Skyscraper, other multi-coloring, XY-Wings and W-Wings, the BUG+3 works as well. |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Thu May 13, 2010 4:16 pm Post subject: |
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"Baphomet" is an example of a discontinuous loop where the given digit used at the start of the loop is eliminated when the loop is followed around to its logical conclusion:
Look at Dan's example for today if we start at r4c4 = 8 you can follow the loop right round and start cell r4c4 <> 8 giving us the r5c5 = 8 of the solution.
There is also the reverse situation where even if you remove the given digit from the start cell the loop will force that value back into the cell.
This thread - Dan's VH 512 in "Other Puzzles"
Start with r8c1 <>1
(25-1)r8c1=r8c6-r6c6=r6c2-r9c2=(1)r8c1; r8c1=1
| Code: | *-----------------------------------------------------------*
| 3 26 58 | 4 1 58 | 9 27 267 |
| 57 78 9 | 58 2 6 | 1 3 4 |
| 26 4 1 | 3 7 9 | 8 25 256 |
|-------------------+-------------------+-------------------|
| 79 5 6 | 29 48 3 | 24 2478 1 |
| 179 3 2 | 19 48 17 | 6 458 58 |
| 8 *17 4 | 6 5 *127 | 3 9 27 |
|-------------------+-------------------+-------------------|
| 256 268 7 | 258 9 4 | 25 1 3 |
|*125 9 3 | 7 6 *125 | 245 248 28 |
| 4 *12 58 | 125 3 1258 | 7 6 9 |
*-----------------------------------------------------------*
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So far, it would seem that an equivalent skyscraper is often present if these 5 sided ones are spotted.
Last edited by Mogulmeister on Thu May 13, 2010 5:25 pm; edited 5 times in total |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Thu May 13, 2010 4:22 pm Post subject: Re: Baphonet and W Wing |
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| George Woods wrote: | | This example of a "Baphomet" might as easily been called a W wing with 48s acting on 8s in col 9 denying the same 4 as the Baphomet |
True George but then what about this example (from Arun's genius puzzle)?
Start r3c9 = 7 ======> r3c9 <> 7
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Thu May 13, 2010 5:53 pm Post subject: |
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I don't know but that looks a text book skyscraper to me!?
Strong link on 7 in row 2 and strong link in row 5 and weak link in column 1. If you think of it as a skyscraper you would also eliminate 7 from r6c8. You can also do the same loop logic starting there.
Aren't all skyscrapers going to exhibit the property you describe? |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Thu May 13, 2010 6:03 pm Post subject: |
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They will indeed but is every Baphomet a skyscraper ? When the discontinuous loop extends to more than "5 sides" what complementary colouring structure will there be ?
I suspect this situation is analagous to the 3 hop XY chain = XY-wing. In Danny's example above, the baphomet is in the horizontal plane but the skyscraper on 8s is in columns 5 and 9 (in the vertical plane).
As many here have commented before, everything is an AIC but this may be helpful to those who are going up the learning curve. For instance, looking at other conversations on this forum , it would appear that not everyone spots skyscrapers easily.
I also appreciate that others are bored rigid by theory discussions.
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Thu May 13, 2010 6:28 pm Post subject: |
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Young girl or Old Lady ?
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Thu May 13, 2010 11:55 pm Post subject: |
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I am sure there are more complicated steps, but I had an XY-wing -248 solving R9C9 as 8.
Keith |
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