Interpretaion of hidden unique rectangle type 2

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Interpretaion of hidden unique rectangle type 2

Postby tonyjer » Thu May 03, 2007 10:04 am

Hi Everyone

This puzzle was posted here a few weeks ago and tried to solve it without reference to the advice given.

Got as far as here and then ran it thru Andrew Stuart's solver which highlighted the hidden UR which eliminates 1 from F4 based on one strong link etc.

I thought I understood most of the UR types but cant see the logic here.

Can someone help me understand how 1 can be removed from the roof tile at F4?

Many thanks.

Tony
Code: Select all
765/?8?/?23
928/?53/67?
134/627/985
5??/?46/7?9
?4?/?7?/?56
6?7/??5/???
45?/7??/36?
??6/5??/?47
87?/?6?/59?
tonyjer
 
Posts: 25
Joined: 22 February 2006

Postby re'born » Thu May 03, 2007 11:01 am

tonyjer,

Your PM grid should be something like:
Code: Select all
 *--------------------------------------------------------------------*
 | 7      6      5      | 149    8      149    | 14     2      3      |
 | 9      2      8      | 14     5      3      | 6      7      14     |
 | 1      3      4      | 6      2      7      | 9      8      5      |
 |----------------------+----------------------+----------------------|
 | 5      18     12     | 1238*  4      6      | 7      13*    9      |
 | 23     4      1239   | 1289   7      129    | 28     5      6      |
 | 6      189    7      | 12389* 139    5      | 248    13*    248    |
 |----------------------+----------------------+----------------------|
 | 4      5      129    | 7      19     1289   | 3      6      128    |
 | 23     19     6      | 5      139    1289   | 128    4      7      |
 | 8      7      123    | 1234   6      124    | 5      9      12     |
 *--------------------------------------------------------------------*


r6c4=1 => r6c8 = 3 => r4c8 = 1. Now the strong link on 3 in row 4 implies that r4c4 = 3. This gives a deadly pattern in r46c48[13]. Hence, r6c4<>1.

This is what Mike Barker called a UR+2B/1SL.
re'born
 
Posts: 551
Joined: 31 May 2007

Thanks for that

Postby tonyjer » Thu May 03, 2007 1:17 pm

Repn'A

Thanks for the prompt reply.

Forgot how to post a grid with candidates. Can you refresh my memory?

Thanks

Tony
tonyjer
 
Posts: 25
Joined: 22 February 2006

Postby underquark » Thu May 03, 2007 5:27 pm

Easiest way is to enter the values into Simple Sudoku, click on the Copy button and paste it into a forum reply, keeping the bit you need (either original values, candidates or both):

*--------------------------------------------------------------------*
| 7 6 5 | 149 8 149 | 14 2 3 |
| 9 2 8 | 14 5 3 | 6 7 14 |
| 1 3 4 | 6 2 7 | 9 8 5 |
|----------------------+----------------------+----------------------|
| 5 18 12 | 1238 4 6 | 7 13 9 |
| 23 4 1239 | 1289 7 129 | 28 5 6 |
| 6 189 7 | 12389 139 5 | 248 13 248 |
|----------------------+----------------------+----------------------|
| 4 5 129 | 7 19 1289 | 3 6 128 |
| 23 19 6 | 5 139 1289 | 128 4 7 |
| 8 7 123 | 1234 6 124 | 5 9 12 |
*--------------------------------------------------------------------*

Then select all the text and click on the "Code" button to get it neat:
Code: Select all
 
 *--------------------------------------------------------------------*
 | 7      6      5      | 149    8      149    | 14     2      3      |
 | 9      2      8      | 14     5      3      | 6      7      14     |
 | 1      3      4      | 6      2      7      | 9      8      5      |
 |----------------------+----------------------+----------------------|
 | 5      18     12     | 1238   4      6      | 7      13     9      |
 | 23     4      1239   | 1289   7      129    | 28     5      6      |
 | 6      189    7      | 12389  139    5      | 248    13     248    |
 |----------------------+----------------------+----------------------|
 | 4      5      129    | 7      19     1289   | 3      6      128    |
 | 23     19     6      | 5      139    1289   | 128    4      7      |
 | 8      7      123    | 1234   6      124    | 5      9      12     |
 *--------------------------------------------------------------------*
underquark
 
Posts: 299
Joined: 06 September 2005

Many thanks

Postby tonyjer » Thu May 03, 2007 7:21 pm

Many thanks for your help

Thanks for your time.

Tony
tonyjer
 
Posts: 25
Joined: 22 February 2006


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