In earlier posts, perhaps in this thread or perhaps in others,

champagne has described two type of 'multi-fish' pattern his programme looks for:

a) with parallel truth sets either in the rows or the columns

b) with truth sets in 2 rows, & 2 columns that intersect in 4 boxes.

I therefore have no problem understanding him, although I would prefer it if two different terms were used. I should hasten to add that not all elimination patterns picked up by b) are recognisable SK loops.

As I see it, these patterns are rank 0 and essentially identify Multi-Sector Locked Sets.

In this row/column multi-fish the MSLS is the 20 cells marked # which contain 20 candidates confined to different houses

....56.8...71.....6.....4.......85...3......29...4..6..1.7.......2.....38...9..5.;55;elev;30;G1

- Code: Select all
` v v v v v`

*----------------------*-----------------------*-----------------------*

| 123-4 249 1349 | 2349 5 6 | 1237-9 8 179 |

>| #2345 4589-2 7 | 1 #238 #2349 | #2369 #239 569 |< 23

| 6 2589 13589 | 2389 237-8 237-9 | 4 123-9 159 |

*----------------------*-----------------------*-----------------------*

| 127-4 2467 146 | 2369 1237-6 8 | 5 137-49 1479 |

>| #1457 3 4568-1 | 569 #167 #1579 | #1789 #1479 2 |< 17

| 9 2578 158 | 235 4 1237-5 | 137-8 6 178 |

*----------------------*-----------------------*-----------------------*

>| #345 1 4569-3 | 7 #2368 #2345 | #2689 #249 4689 |< 23

>| #457 4569-7 2 | 4568 #168 #145 | #16789 #1479 3 |< 17

| 8 467 346 | 2346 9 123-4 | 127-6 5 1467 |

*----------------------*-----------------------*-----------------------*

^ ^ ^ ^ ^

45 68 459 689 49

Multi-sector Locked Set:(23)r2,(17)r5,(23)r7,(17)r8,(45)c1,(68)c5,(459)c6,(689)c7,(49)c8

17 Eliminations in 16 cells

In

pjb's three examples the MSLSs are the 16 cells, r28c1379,c28r1379 which contain 16 candidates confined to different houses.

For the 3rd example: Multi-sector Locked Set:(59)r2,(27)r8,(47)c2,(25)c8,(18)b1,(36)b3,(36)b7,(18)b9

Of course, truth and link sets aren't the only way to find MSLSs

I assume that with Xsudo, setting these cells as cell truth sets, would then automatically produce the link sets to accompany them – although the notations would be longer than using the MSLSs. The question then arises what rank zero patterns should be classed as multi-fish? Having only a casual acquaintance with truth and link sets I can't say.

pjb you may find that in addition to allowing an 'occasional' box link set, if you also allowed an 'occasional' box truth set, your problem might be solved.