A General Logic for Sudoku

Golden Nugget

 

 

Elimination 19

 

Elimination 19 again takes the form of a layered structure like elimination 1. In this case, 3 of the 4 single digit layers form strong inference sets that combine in a group 4 vertical linksets. Each of the layers guarantees that 1 candidate is in the linksets thus 3 of the 4 nodes at digit layer 2 must be empty. This raises the rank in level 2 and forces linkset 2c4 to be rank 0, thus eliminating 2r1c4. Linkset 2r4 is highlighted black in the diagrams below. 

 

 

 

Another view of the elimination showing rank 0 linkset 2r4 highlighted black and the SIS at level 4 highlighted with pink cubes.

Logic Diagram

 

Below is a set/linkset logic diagram for the elimination showing the 4 logical layers for (top to bottom) digits 1, 2, 4, and 7.  Each of the 3 strong inference sets is indicated as SIS.  The added effect of the 3 SIS is input to digit layer 4. All nodes are rcn notation

 

p321=p121A==p131                                                                                            

 \_____|_____/

 /           \

 |          p171B=========================p391==p381                                                 

 |           |                              |     |

p721========p771==p741=====================|=====|==========p791                                     

             |     |                       |     |           |

            p471==p441=====================|=====|====p481   |                                        

                    SIS 1 ---->            |     |     |     |

                                           |     |     |     |          p632========p132

                                           |     |     |     |           |          p232

                                           |     |     |     +--+        |           |

                     Level 2 ---->         |     |     |     | p792H=====|====p742   |               

                                           |     |     |     |    \      |     |     |

                                           |    p382C=p482===|====p982==p682   |     |               

                                           |     |     |     |                 |     |

                                          p392==p382C==|=====|================p342==p312

                   SIS 2 ---->             |     |     |     |

                        p174==============p394F=p384D  |     |                                       

                        p274               |     |     |     |                                       

                         |                 |     |     |     |

                         |    p324==p364==p394F=p384D  |     |                                       

                         |     |     |     |     |     |     |

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

                         |           |     |     |     |     |

                        p774========p764===|=====|=====|====p794                                     

                   SIS 3 ---->             |     |     |

                                          p397G=p387E==|======================p367 

                                           |    |      |                       |

                                          p397G=p387E==|================p277   |   

                                                       |                 |     |

                                                      p487==============p477==p467 

 

 

Logic and Grid

rank 2: S15={247r3 147r4 124r7 2c38 1b1 147b3},

L17={1r1 2r6 14c2 12c4 47c6 147c7 3n89 4n8 7n9 2b19}

=> (2c4) => r1c4<>2

 

-------------------------------------------------------------------------------

| 25678   458*1   457*12  | 268     2467    4678    | 2*14    3       9       |

| 289     489     47*2    | 389     2347    1       | 2*47    6       5       |

| 69*2    69*14   3       | 69*2    5       9*47    | 8       *1247   *1247   |

-------------------------------------------------------------------------------

| 235     35*4    8       | 5*1     9       35*7    | 235*147 *1247   6       |

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

| 1       3569    56*2    | 4       367     35678   | 23579   789*2   378     |

-------------------------------------------------------------------------------

| 367     36*1    9       | 6*12    8       36*4    | 37*14   5       *124    |

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

| 4       13568   156     | 7       1236    3569    | 139     189*2   1238    |

-------------------------------------------------------------------------------

 


 
 
 


 
 
 

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