As long as the als a - als b cells are in the same band/stack and intersection contains all the restricted digits then it  falls within a barn constructions by my definitions which is an over simplified als xz system 
And can go from size 1-8 cells with 9 digits on both a and b als.  (as Long as the total cell count = the total digit count) {then i use a hybrid als-xz rule coupled with subset counting to make eliminations} 
there by a 
RSTUVWXYZ - WING IS plausible.
ps:  These  also includes double linked rule on my 
barns pagei posted this over on 
Andrews stewards page to hopefully get him to update his als-xz engine as a test case... 
- Code: Select all
- .---------------.------------.-----------------.
 | 5    478  1   | 2   6   3  | 789    78    49 |
 | 34   6    247 | 1   8   9  | 237    5     34 |
 | 9    238  28  | 7   5   4  | 2368   2368  1  |
 :---------------+------------+-----------------:
 | 2    9    3   | 6   4   8  | 5      1     7  |
 | 48   478  478 | 59  19  15 | 236    236   36 |
 | 1    5    6   | 3   2   7  | 4      9     8  |
 :---------------+------------+-----------------:
 | 7    38   5   | 4   19  6  | 1389   38    2  |
 | 36   1    9   | 8   7   2  | 36     4     5  |
 | 468  248  248 | 59  3   15 | 16789  678   69 |
 '---------------'------------'-----------------'
 
case study puzzle for technique testing.
als-xz double linked rule can and does apply to some formations of
wxyz-wings:
Almost Locked Set XZ-Rule {double link rule}: A=r1c8 {78}, B=r79c8,r8c7 {3678}, X=7,8 => r3c8<>8, r7c7<>3, r9c79<>6
double linked rule is pretty simple: 
 For each digit in A and not in B are restricted to A cells. all peers of these cells may be eliminated  for said digit.
 For each digit in B and not in A are restricted to B cells all peers of these cells may be eliminated for said digit.
For each digit in A & B are restricted to A & B cells, all peers of these cells may be eliminated for said digit. 
I created  B.A.R.N.(s) merely because John refused to accept that. early xy, xyz, Wxyz wings{predominantly this issue}, sue du coq, ape, ate, all fall under Als rules developed later on and there by its extensions should and can apply extending the reach of those Technique where applicable.{in some cases simplified or obsoleted the technique completely} 
 Which is what I did by early on for
Wxyz wing extensions from the old forum be for the crash.
it originally covered all permutations of this technique, and later compressed the list down to 4 basic formations. With some context on extending it beyond 4 cells and 4 digits, and some notes on sub-classes for an almost almost locked version that mimicked als-Xy rule as a potential almost almost locked Set xz rule.
 {which is what lead to me and john headbutting over the named technique shouldn't be extended etc when he discovered my suggestion over 3 years after the fact and I already had the work in place and finally convinced Andrew to updated his solver to reflect the idea and improved its effectiveness of this extremely rare function by over ~1500% putting the technique back into his solver! instead of scrapped} 
 John still refuses to accept my wxyz-wing extensions  as Wxyz wings even after a two year debate... so I took his self dubbed idea in my name and came up with a "barns" definition which for what ever reason he now also Defers it to some one Else's definition again leading to more arguments. (never ending battle as he won't join this site for rational discussion and instead refers to his own lingo on the blog...= Much confusion when trying to point stuff out.) 
interesting to see an Al's xy double linked rule I've been working on that idea with my new code engine. I'll have to check that out as well.. 
( a loop rule for start and end als using same set is also applicable in these cases)
Subset counting covers alot of stuff, and has extension as well: 
Disjointed Distributed Subset  and obiwans 
Almost Disjointed distributed subset i do have dds and adds coded into my solver and my barn code is technically based on subset-counting and als-xz rules for eliminations   
as far as i'm aware:  
mike baker, 
myth jellies,
danny, 
obi and 
pascal and possibly 
Ronk & 
Ruud had the only fully implemented subset functions.. {none of these guys have been on in 3-6+ years} {since the programmers forum became obsolete,and ours was kindly relocated here in.}