A General Logic for Sudoku

Golden Nugget

 

 

Elimination 23x

 

 

 

Elimination 23x is an elimination from a previous solution to Golden Nugget.  It is a rank 4 structure that uses all its triplets to raise the rank to 1 at the elimination side, in spite of the fact that two triplets cannot be occupied at the same time. This emphasizes that triplets can raise the rank whether occupied or not.  Se the simplified logic diagram below for an explanation.

 

 

 

 

Set Logic and Grid

 

E23[ 24 Nodes, Rank 4:

     8 Sets = {2479r3 247r4 2n7}

     12 Links = {2c1 4c2 7c6 247c7 3n46 4n8 247b3}

     --> (7c7*7b3) => r1c7<>7

 

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

  | 257    145    12457  | 68     2467   678    | 1247   3      9      |

  | 89     89     2467   | 3      247    1      | (247)  267    5      |

  | 6(2)   16(4)  3      | (29)   5      (479)  | 8      16(247 1(47)  |

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

  | 3(2)   35(4)  8      | 15     9      35(7)  | 15(247 1(247) 6      |

  | 3569   7      456    | 1568   136    2      | 13459  1489   138    |

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

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

  | 367    136    9      | 126    8      346    | 1347   5      124    |

  | 358    2      157    | 159    134    3459   | 6      14789  13478  |

  | 4      3568   156    | 7      1236   3569   | 1239   189    1238   |

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

 

Logic Diagram

 

The following is a simplified logic diagram to demonstrate the principle. The tri0plets p272 and p274 are the focus. One must be occupied and the other unoccupied. The occupied one reduces the overall rank by occupying 2 linksets simultaneously, while the unoccupied one must reduce the rank along its minor path, i.e., in the direction of the elimination. The pair lowers the rank by two, combined with the third triplet produces the elimination.

 

 

        p367C=====p387

        /   \      |

       /     \     |     

       |     |     +-----X (target)

       |     |           |

       |     |           |

       |    p467==p487==p477                             

       |           |    

      (|)         (|)     <----Rank 1 region.

       |           |    

       |           |            p272A=======p274B             

       |           |            /   \       /   \

       |           |           /     \     /     \

       |           |           |     |     |     |

      p369=========|===========|=====|=====|=====|====p349

       |           |           |     |     |     |     |

       |           |          p382===|=====|=====|====p342==p312  

       |           |                 |     |     |           |

       |          p482==============p472===|=====|==========p412 

       |           |                       |     |

       |          p484====================p474===|================p424 

       |                                         |                 |

      p364======================================p384==============p324