denis_berthier wrote:.
Maybe a simpler question.
Suppose you filter all the complete solution grids in several stages:
- first stage: does it have a solution tridagon? From my calculations, we already know that ~50% will pass this stage and that, in the T&E(3) domain, we'll miss ~15-20% grids that may have minimal puzzles with a non-degenerate tridagon;
- second stage for a grid having passed the first: does it have at least one minimal puzzle with a non-degenerate tridagon. At this point already, it seems we don't know the answer about the proportion that pass the test (at least, I'ven't seen any answer).
- third stage for a grid having passed the second one: does it have at least one minimal puzzle with a non-degenerate tridagon AND sufficiently hard (e.g. at least in T&E(2) or with at least SER 11.x - choose x as you like). Here also, it seems we have no answer - because the answer is intractable.
Anything to add about the above 3 points?
champagne wrote:One remark : a solution grid can have several "magic square" here an example for the grid rank 132808
267983154938415762541726398123564879789231546456897213612379485895142637374658921;132808
514839276672154983938267514123978465789645132456312798367421859291586347845793621;132808
367895124291374685845612397789123546123456879456789213938541762672938451514267938;132808
214958637865743921937126485123897546456231879789564213541389762398672154672415398;132808
To answer the "second stage" question ...
Here is an example of a "maximal" puzzle with a non-degenerate tridagon with one true guardian.
- Code: Select all
+----------------+---------------+-------------+
| 4 5 123 | 123 6 7 | 123 8 9 |
| 8 123 7 | 9 123 4 | 123 5 6 |
| 1239 123 6 | 5 8 123 | 4 123 7 |
+----------------+---------------+-------------+
| 123 4 5 | 123 7 9 | 6 123 8 |
| 7 123 8 | 6 123 5 | 9 123 4 |
| 6 9 123 | 8 4 123 | 123 7 5 |
+----------------+---------------+-------------+
| 12 8 9 | 12 5 6 | 7 4 3 |
| 23 6 4 | 7 23 8 | 5 9 1 |
| 5 7 13 | 4 9 13 | 8 6 2 |
+----------------+---------------+-------------+
There are 2,968,332,766 puzzles like that, on 1,807,371,808 solution grids.
Any minimal puzzle with a non-degenerate tridagon with one true guardian, is (isomorphic to) a minimized version of one of the "maximals".
Aside: Displaying the "maximal" puzzle above, as a pencilmark diagram, was a little misleading.
Most of the puzzles have a one or two naked singles for tridagon digits, in boxes 3,6,7 or 8.
I had to go through a few of them before I found one that was suitable.
---
Trivia: 18 of the grids, have 24 maximal puzzles. None have more than 24.
The breakdown by "puzzles per grid", looks like this:
- Code: Select all
Np | Grids | Puzzles
----+------------+-----------
24 | 18 | 432
22 | 7 | 154
21 | 1 | 21
20 | 210 | 4200
19 | 12 | 228
18 | 184 | 3312
17 | 85 | 1445
16 | 595 | 9520
15 | 463 | 6945
14 | 1929 | 27006
13 | 4061 | 52793
12 | 12593 | 151116
11 | 27669 | 304359
10 | 80662 | 806620
9 | 240572 | 2165148
8 | 762245 | 6097960
7 | 2070808 | 14495656
6 | 7473886 | 44843316
5 | 22319557 | 111597785
4 | 71818891 | 287275564
3 | 135488290 | 406464870
2 | 526955246 | 1053910492
1 | 1040113824 | 1040113824
----+------------+-----------
| 1807371808 | 2968332766
Here are the puzzles for one of the "24-puzzle" grids:
- Code: Select all
.234.678.4.678..2378..234.623...76.8.6483..728.72643..3.2978.646783452...4.612837 (159)
.234.678.4.678..2378..234.623...7648.6483..728.72.43..3.2.7856467834.291.4.6.2837 (159)
.234.678.4.678..2378..234.623...7648.6483.9728.72643153.2.78.6467.34.2...4.6.2837 (159)
.234.678.4.678..2378..234.6231..764856483..728972643..3.2.78.6467834.2...4.6.283. (159)
.2345.7.945.7.9.237.9.2345.23.59..4.5.4.3.972.972.43.53.297.564.7.345291945..2837 (168)
.2345.7.945.7.9.237.9.2345.23.597.4.5.4.3..72.972.43.53.29785.4.7.34529.945612.37 (168)
.2345.7.945.7.9.237.9.2345.23.597.4.5.4831972.972643.53.297.5.4.7.34529.94...2.37 (168)
.2345.7.945.7.9.237.9.2345.231597.4.564.3.9728972.43.53.297.5.4.7.3.529.945..2.37 (168)
1.3.5678..5678.1.378.1.3.56.315.76.856.83..7.8.7.6.31531..785646783.5291..561.837 (249)
1.3.5678..5678.1.378.1.3.56.315.76.856.831.7.8.7.6..1531.97856.678345..1..5612837 (249)
1.3.5678..5678.1.378.1.3.56.315.764856.8319728.7.6.31531..7856.6.83.5..1..561.837 (249)
1.3.5678..5678.1.378.1.3.562315.76.8564831.7.897.6.31531..7856.6783.5..1..561..37 (249)
1.345..8945..891.3.891.345..3159..485.48.19..89...431531.9.8564..8345291945.1.837 (267)
1.345..8945..891.3.891.345..3159..485.48319..89...43.531.9785.4..8345.9194561283. (267)
1.345..8945..891.3.891.345..31597.485.48319..89.26431531.9.85.4..8345.919.5.1.83. (267)
1.345..8945..891.3.891.345.23159..485648319..897..431531.9.85.4..834..91945.1.83. (267)
12..567.9.567.912.7.912..562.15.76..56...1972.9726..15.1297.56467...52919.5612837 (348)
12..567.9.567.912.7.912..562.15976..56...19.2.9726..15.1297856.67.3452919.5612..7 (348)
12..567.9.567.912.7.912..562.15976..56.831972.97264.15.1297.56.67...5.919.5612..7 (348)
12..567.9.567.912.7.912..562.159764856...1972.9726.315.1297.56.67...52919.56.2..7 (348)
12.4.6.894.6.8912..8912.4.62.1.9..48.648.19.289.264.1..12978.646.834529194.6128.. (357)
12.4.6.894.6.8912..8912.4.62.1.9.648.648.19.289.26..1..129.85646.8.4.29194.612837 (357)
12.4.6.894.6.8912..8912.4.62.1.9.648.648.197289.264315.129.8.646.8.4.29194.61.8.. (357)
12.4.6.894.6.8912..8912.4.62.1597648.648319.289.264.1..129.8.646.8.4.29.94.6128.. (357)