A General Logic for Sudoku

Golden Nugget

 

 

Elimination 1, The Layer Cake

 

 

This first elimination takes the interesting form of a layered cake, as seen in the small right image. Each of the 5 single digit layers forms a strong inference set, all of which combine in the same group of 5 vertical linksets. Each of the layers guarantees one candidate in the 5 linksets thus the linksets must each have one to form a rank 0 region. The eliminatee sits in one of the rank 0 linksets. Other eliminations from Golden Nugget show similar layering effects so the layered method suggested by the solver might be showing a weakness in the puzzle that can be exploited.

 

 

Logic Diagram

 

Below is a set/linkset logic diagram for the elimination showing the 5 logical layers for (top to bottom) digits 1, 2, 4, 6, and 7.  Each of the 5 strong inference sets is indicated as a SIS.  Nodes are represented in NCR notation. (NOTE: this diagram is an update, many of the older diagrams are in RCN notation)

 

     1c7  2c7  1c2  1b1  2c1  1c4  2c4  7n9  3n9  3n8  2n8  4n8  4c6  7c1  4c2  7c6  4c7  7c7

 

1R1: 117=======112A=112A

      |         |   113                                              }

      |         |    |                                               }

1R3:  |        132B=132B=====================139==138                }

      |         |                             |    |                 }  SIS 1

1R7: 177=======172============174=======179   |    |                 }

      |                        |         |    |    |                 }

1R4: 147======================144========|====|====|========148      }

                                         |    |    |         |

2B3:      217============================|===239F=238C=228   |          }

          227                            |    |    |    |    |          }

           |                             |    |    |    |    |          }

2R7:      277======================274==279   |    |    |    |          }  SIS 2

           |                        |    |    |    |    |    |          }

2R3:       |             231=======234===|===239F=238C  |    |          }

           |              |              |    |    |    |    |          }

2R4:      247============241=============|====|====|====|===248         }

                                         |    |    |    |    |

6C8:                                     |    |   638==628   |             }  SIS 3

                                         |    |    |    |    |

4B3:                         {           |   439G=438D=428===|=======================417

                             {           |    |    |    |    |                       427

                             {           |    |    |    |    |                        |

4R4:                  SIS 4  {           |    |    |    |   448============442=======447

                             {           |    |    |    |    |              |         |

4R3:                         {           |   439G=438D==|====|===436=======432        |

                             {           |    |    |    |    |    |                   |

4R7:                         {          479===|====|====|====|===476=================477

                                         |    |    |    |    |

7B3:                           {         |   739H=738E=728===|============================717

                               {         |    |    |         |                            727

                               {         |    |    |         |                             |

7R4:                    SIS 5  {         |    |    |        748=================746=======747

                               {         |    |    |                             |         |

7R3:                           {         |   739H=738E================731=======736        |

                               {         |                             |                   |

7R7:                           {        779===========================771=================777

                                                                                              

Logic and Grid

 

E1b  54 Nodes, Raw Rank = 1 (linksets - sets)

     17 Sets = {1r1347 2r347 4r347 7r347 6c8 247b3}

     18 Links = {27c1 14c2 12c4 47c6 1247c7 234n8 37n9 1b1}

     --> (7n9) => r7c9<>3

 

  +--------------------------------------------------------------------------------------+

  | 25678    4568(1)  24567(1) | 268      2467     4678     | (1247)   3        9        |

  | 26789    4689     2467     | 23689    23467    1        | (247)    (2467)   5        |

  | 69(27)   69(14)   3        | 69(2)    5        69(47)   | 8        (12467)  (1247)   |

  +--------------------------------------------------------------------------------------+

  | 35(2)    35(4)    8        | 35(1)    9        35(7)    | 35(1247) (1247)   6        |

  | 3569     7        456      | 13568    136      2        | 13459    1489     1348     |

  | 1        3569     256      | 4        367      35678    | 23579    2789     2378     |

  +--------------------------------------------------------------------------------------+

  | 36(7)    36(1)    9        | 36(12)   8        36(4)    | 3(1247)  5        -3(1247) |

  | 3578     2        157      | 1359     134      3459     | 6        14789    13478    |

  | 4        13568    156      | 7        1236     3569     | 1239     1289     1238     |

  +--------------------------------------------------------------------------------------+


 
 
 


 
 
 

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