Hi,
blueblue wrote:Serg wrote:Definition
SudokuP Validity Preserving Group or PVP Group is group of transformations preserving validity of any valid SudokuP puzzle or solution grid. This group is generated by following set of transformations and is subgroup of VPT Group.
1. Transposing.
2. Permutations of 3 bands.
3. Permutations of 3 stacks.
4. The same permutations of rows in every band.
5. The same permutations of columns in every stack.
Totally we have 2 x 6^4 = 2592 isomorphic transformations.
I argued earlier that this isn't the
full "PVP" group.
I won't labor the point, but it's the intersection of the "full group" with the Sudoku VPT group.
I think you mean, that there are extra transformations preserving validity of some SudokuP puzzles or solution grids (for example, F-transformation). Those transformations don't participate PVP Group, so this group isn't full. But F-transformation isn't universal, i.e. it preserves validity of
some SudokuP solution grids, but doesn't preserve validity of others. I wrote in my definition "PVP Group is group of transformations preserving validity of
any valid SudokuP puzzle or solution grid", therefore F-transformation cannot participate this group. You can define another group (or set) of transformations including F-transformation, but that definition will define another kind of equivalence. When we say "there are 214,038,113 P-different SudokuP solutions grids" we mean that neither solution grid among those 214,038,113 SudokuP grids can be transformed to another by some transformation from PVP Group. One can define another kind of equivalency and get another number of X-equivalent SudokuP grids. But it doesn't imply that my definition of PVP Group is wrong.
I remember similar discussion years ago - should we treat "twin" valid sudoku puzzles, having unhitted UA sets among their clues and being transformed to each other by UA sets permutations, as different puzzles. Such "twins" have
the same solution paths, so they are equivalent in wide sense. But when we say "essentially different" sudoku puzzles, we mean that neither of those puzzles can be transformed to another puzzle by one of 3,359,232 isomorphic transformations. This is question of definitions.
Serg