The New Sudoku Players' Forum

[SteveG48]

I agree with Danny: a hidden triple in c1, doesn't eliminate candidates in c9.

IMO this should be written as:

1r3c7 = (1-4)r3c1 = HP(48)r89c1 - 2r9c1 = r7c1 - r7c9 = 2r3c9 => -2r3c7

Oddly enough, a hidden triple does come up in a right to left reading:

2r3c9 = r7c9 - r7c1 = HT(248)r379c1 - 1r3c1 = 1r3c7 => -2r3c7

In line with David's comment:

The internal inference in an AHS is weak - [...]

... those could be better written as:

1r3c7 = (1-4)r3c1 = HP(48-2)r89c1 = r7c1 - r7c9 = 2r3c9 => -2r3c7
2r3c9 = r7c9 - r7c1 = HT(248-1)r389c1 = 1r3c7 => -2r3c7

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On the lighter side (but somewhat seriously) ...

Using the forms above, why even bother with the "HP" and "HT" text ? ... why not these instead ?

1r3c7 = (1-4)r3c1 = (48-2)r89c1 = r7c1 - r7c9 = 2r3c9 => -2r3c7
2r3c9 = r7c9 - r7c1 = (248-1)r389c1 = 1r3c7 => -2r3c7

From the dark side ...

Maybe because it would invite this kind of shortening:

1r3c7 = (1-4)r3c1 = (4-2)r89c1 = r7c1 - r7c9 = 2r3c9 => -2r3c7
2r3c9 = r7c9 - r7c1 = (2-1)r389c1 = 1r3c7 => -2r3c7

On the other hand, I can accept those as easily as I can the (commonly used) ANS notation:

1r3c7 = r3c1 - (1=2)r14567c1 - r7c9 = 2r3c9 => -2r3c7
2r3c9 = r7c9 - (2=1)r14567c1 - r3c1 = 1r3c7 => -2r3c7

Opinions ?

I personally prefer the ANS notation, but I see no logical reason to exclude any of the forms that have been discussed; that being why I questioned Danny's thoughts on the matter.

[DonM]

On the lighter side (but somewhat seriously) ...

Using the forms above, why even bother with the "HP" and "HT" text ? ... why not these instead ?

1r3c7 = (1-4)r3c1 = (48-2)r89c1 = r7c1 - r7c9 = 2r3c9 => -2r3c7
2r3c9 = r7c9 - r7c1 = (248-1)r389c1 = 1r3c7 => -2r3c7

Cheers,
Blue.

The HP & HT, just as other descriptive abbreviations, benefit the reader so as not having to take that extra step to figure out what operative is being used. Unfortunately, we're seeing a marked trend on this forum where too often individuals are determined to use as minimal notation as possible, use their own non-standard abbreviations or, even worse, use their own notation (which probably no one is following).