The New Sudoku Players' Forum

[little Zivvy]

Scrose,

Many thanks for the excellent reply.

You are right, the 2s are easiest once you know what you're doing

I guess I need more practice, but your post above has really cleared some things up.

Now I can go back to see if I can now solve some other puzzles where I had got to similar positions as the above puzzle, and see if I can crack em now.

[Nick70]

However, isn't this really another (very clever) way of solving using proof by contradiction, where using colors in this way is just another way of testing one hypothesis? Anyhow, I'm not trying to argue your solution is invalid.

This has already been discussed with tso in other threads, but essentially, there is nothing wrong in proof by contradiction. It is logic. In my example above, I didn't elevate any number to the rank of "test candidate". I simply evaluated the relationship between pairs of (cell,value) possibilities, and drew conclusions from that, which allowed me to put a number in a cell.

[dukuso]

here is a statistics, how the chutes in gfroyle's
450 sudokus with 17 clues distribute
in the "gang of the 44" :


1
2
3 oooo
4
5
6
7
8 oooo
9 oooooooooooo
10 oooooo
11 oooooooooooo
12 ooooo
13 o
14 oooooooooooooo
15 ooooooo
16 oooo
17 oooooooooooooo
18 oooooooooooooooooooooo
19 oooooooo
20 oo
21 ooooo
22 ooooooooooooo
23 ooooo
24 ooooooooooo
25 oooooooooooooooooooooo
26 oo
27 ooooooo
28 ooooooooooooo
29 oooooooooooooooo
30 ooo
31 ooooooooooo
32 ooooooooooooooo
33 oooooooooooooo
34 oooooooooooo
35 ooooooooooooooooooooooooooooooooooooooooooooooo
36 ooooooooooooooooooooo
37 oooooooooooooooooooooooooooooooooooooooooooooooooooooooo
38 oooooo
39 ooooooooooooooooooo
40
41 ooo
42
43 ooooo
44

[angusj]

here is a statistics, how the chutes in gfroyle's
450 sudokus with 17 clues distribute
in the "gang of the 44"

Could you please explain what the "gang of the 44" is to the simple minded (ie me)?

[dukuso]

see the long thread about sudoku's maths for the
"gang of the 44"

http://forum.enjoysudoku.com/viewtopic.php?t=44&postdays=0&postorder=asc&start=225



each 3*9 chute in a sudoku is from one of the 44 classes.
Allowed operations are:
permute the symbols
permute columns 1,2,3
permute columns 4,5,6
permute columns 7,8,9
permute the 3 blocks
permute the entries in mini-column 1
permute the entries in mini-column 2
...
permute the entries in mini-column 9


this gives 6 numbers from 1..44 for the 6 chutes in a sudoku
to characterize the type of a sudoku.