A General Logic for Sudoku

Monster #224 from list 1465

This is part of a set-logic solution to monster puzzle #224 from the 1465 list. The original solution to the puzzle (by ttt) was presented here. The elimination logic has the form:

rank N(n sets+ m linksets), [ cover set list ]x[ cover linkset list ] reason for elimination => results

For more information on notation and set logic eliminations, see quick reference. For a full description of sets and Sudoku set logic, see the SudokuOne.com website. The entire set logic solution is here.

Elimination 17, Discontinuous Nice Multi-loop with ALS

Rows 1 2 and 3 contain part of a discontinuous nice loop with 2 strong links that meet at 6r3c6 to assign the candidate. However, part of the loop in rows 4 and 5 is made of a rank 1 dual loop that connects to the DNL through linkset triplet 6r4c3. The set logic notation for the elimination is:

Rank 0(8+8), [6r3 9r5 26c6 4n8 36b3 1b5]x[6r4 3c8 1n9 4n6 5n46 6b2 9b6]

6r3*6b3 => 6r3c9, r1c9<>6, r3c4<>6 (singles to the end)