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 4, Finned X-Wing + ALS Chain for 2nd Fin

This logic would be a dual finned X-wing in row sets, 3r36c146, with one fin in box set 6b2. The other fin that would be in 6b5 is covered by a short ALS chain, 6r6c(6-4)=4r6c4-(als)456r78c4-6r36c4. The set logic notation for the elimination is:

Rank 1(5+6), [6r36 78n7 4b6]x[6c4 456c7 6n9 6b3] 6c7*6b3 => r2c7<>6