## VWXYZ-Wing?

Post the puzzle or solving technique that's causing you trouble and someone will help

### Re: VWXYZ-Wing?

How do subset counting and Barn handle this:

Code: Select all
Code: Select all
`   .--------------------.--------------.----------------------.    | 234579  2579  234  | 134  8    49 |  14569  5679  124579 |    | 23459   259   1    | 7    349  6  |  8      59    2459   |    | 4789    6     48   | 5    149  2  |  149    3     1479   |    :--------------------+--------------+----------------------:    | 269     4     7    | 26   269  58 |  3      1     58     |    | 1       29    23   | 234  7    58 |  459    589   6      |    | 36      8     5    | 136  136  49 |  7      2     49     |    :--------------------+--------------+----------------------:    | 2578    3    a268  | 9   a26   1  |ab56     4    b578    |    | 457     157   9    | 8    46   3  |  2     b567   17-5   |    | 248     12    2468 | 246  5    7  |  169    689   3      |    '--------------------'--------------'----------------------'`

(5=268)r7c357 - (8=675)b9p135 => -5 r8c9

What we have is an overlapping ALS XZ: a=(2568)r7c357, b=(5678)b9p135, x=8, z=5). Subset counting gives: [25678] -> [11211] (+1). Our elimination does not make that sum negative (only zero). How does subset counting work with overlapping ALS moves?

SpAce

Posts: 283
Joined: 22 May 2017

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from my barn code. {and als-xz} {ps my grid system is 0..80 top left to top right and top down order. }

Set a) 2568 @ Cells 56,58,60
Seb b) 5678 @ cells 60,62,70
x = 8, Z = 5,6

61,69,71,78,79,80 <> 5
61 <> 6

or

Set a) 25678 @ cells 56,58,60,62
Set b) 567 @ cells 60,70
x =7, z = 5,6
61,69,71,78,79,80 <> 5
61 <> 6

overlaps are fine as long as they do not contain all the RC of one or both of the overlapping sectors.

for subset counting making the count negative gives direct true eliminations, when a subset with in the cells are "connected" by a subset the zero can force a negative number which is where Almost DDS plays an effect. {as wrote by obiwan} as a person would also checking the subsets counts.

in this case the RC of either 7 or 8 {depending on which of the two is used} contains any of the common digits 5,6 and directly sees a bivalve which shares a "0" sector by placement also reduces the count by 1.

probably something much easier then that to do it... like an counting method that checks that all A&B sectors are eliminated reducing the count twice instead of once...

ps. if you didn't read in one of the linked threads i listed a Sue de coq is the simplest subset counting method as it is a 2 sector disjointed subset.
which is replicated by als-xz double linked rule.

and a death blossom is a 3 sector disjointed subset aka {als-xy rules}
Some do, some teach, the rest look it up.

StrmCkr

Posts: 840
Joined: 05 September 2006

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