The New Sudoku Players' Forum

[botofrank]

I’m new here and I would like to understand the Legend in formulas.
For example what does it mean
(5=419)b8p467 - r5c6 = (5)r5c6 => -5 r5c4; 4 placements or
(5)r9c4 = r9c2 - r1c2 = (5)r1c45 => -5 r2c4, etc.

[Mauriès Robert]

Hi,

I’m new here and I would like to understand the Legend in formulas.
For example what does it mean
(5=419)b8p467 - r5c6 = (5)r5c6 => -5 r5c4; 4 placements or
(5)r9c4 = r9c2 - r1c2 = (5)r1c45 => -5 r2c4, etc.

These sequences are AICs describing the construction of an alternating chain of strong (=) and weak (-) links which can be explained like this, for example for the second AIC :
If 5r9c4 false=>5r9c2 true=>5r1c2 false=>5r1c45 true => that any candidate of occurrence 5 who sees 5r9c4 and 5r1c45 can be eliminated, which is the case of 5r2c4.
Robert

[botofrank]

Hi Robert,
Thank you for the explanation.
The AIC (Alternating Inference Chain) is the new concept for me.
So, I need to learn this topic deeper in order to understand description in some puzzles.
Thanks again, botofrank.