Not sure if these are Remote Pairs

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Not sure if these are Remote Pairs

Postby Audres » Thu Apr 17, 2014 1:38 pm

Hello, I'm a newbe to this forum and to sudoku and to posting in general.

My concern is that I encountered what could be Rremote Pairs of 1 and 6 in R9C35 and R8C58. The puzzle is from Andoku. When opened with Hoduku it reported an invalid puzzle. Sadman solved it placing a 3 in R7C8. My confusion is that it appears to consider R7C3 as part of the pairs, even if that cell has a 5 in it. I am also confused because I thought that remote pairs hat to be an even number. Sadmans solution appears to consider 5 Remote Pairs.

Any suggstion?
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remote pairs.png
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Re: Not sure if these are Remote Pairs

Postby JasonLion » Thu Apr 17, 2014 6:23 pm

That is certainly a valid puzzle.

There isn't anything useful you can do with the Remote Pair you mention, at least using the simpler definition of remote pairs. However I have seen a more complex definition that incorporates ideas from unique rectangles. Using that more complex version there is an elimination that can be made. Using the Unique Rectangle type 4 principal combined with the four cells you mentioned, since R7C38 must contain 6, it can't contain 1. This pattern works with six cells, R9C35, R8C58, and R7C38.
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Re: Not sure if these are Remote Pairs

Postby Audres » Fri Apr 18, 2014 12:22 am

Makes sense. Very helpful, thanks a lot.
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Re: Not sure if these are Remote Pairs

Postby Leren » Fri Apr 18, 2014 6:03 am

Hi Audres,

Your diagram shows that 8 can only go in Column 1 of Row 2, so you can immediately solve that cell.

Also in Row 9 there is a naked pair 16 in Columns 3 and 5, so you can remove the 1 from r9c1.

After that there is an XWing in 1's in Columns 1 and 9, Rows 3 and 7, which removes the 1 's from r7c3 and r7c8.

Finally there is a W Wing (23) in r1c9 and r2c2 linked by a pair of 2's in Column 3, which removes the 3's from r1c1 and r2c8.

Thereafter the puzzle solves by a cascade of singles.

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Re: Not sure if these are Remote Pairs

Postby RyanStorm » Sun May 04, 2014 5:44 am

At bottom, you got them 1 or 6's across bottom row, well that means the bottom left 1, 3 or 7, you can erase the 1, because there will be a 1 or 6 in the other two. That doesn't add anything, but it narrows that down.
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