Search found 85 matches

by Mephisto
Sat 21 Nov, 2020 4:06 pm
Forum: Puzzle (incl. Sudoku) Rules & Tips
Topic: Four Winds
Replies: 8
Views: 3069

Re: Four Winds

@Gareth: Not necessarily. IMHO if a cell remains empty, it is not reachable at all. Or can you post a contra-example (which has only one solution)?
by Mephisto
Wed 18 Nov, 2020 11:21 am
Forum: Puzzle Competitions
Topic: Notation for Sudoku
Replies: 4
Views: 2191

Re: Notation for Sudoku

I am more than skeptical. I also doubt whether anyone is willing to internalize and apply the suggested notation. In principle, an algorithm is needed to solve Sudoku and algorithms are usually described with programming languages. Do we now want to invent a Sudoku programming language? By the way, ...
by Mephisto
Mon 16 Nov, 2020 9:44 am
Forum: Puzzle (incl. Sudoku) Rules & Tips
Topic: General Puzzle Rules & Definitions
Replies: 15
Views: 30073

Re: General Puzzle Rules & Definitions

Your answer does not address my complaints. If you deduce R3C5 = 3 or 5, you don't know that both are right -- so you have to guess. (There is no way to deduce that both numbers are right! You most likely assume that your logical skills are insufficient at this point.)
by Mephisto
Thu 12 Nov, 2020 7:29 am
Forum: Puzzle (incl. Sudoku) Rules & Tips
Topic: General Puzzle Rules & Definitions
Replies: 15
Views: 30073

Re: General Puzzle Rules & Definitions

If there are two solutions, there is no logical way to decide which part of the solution path the solver should take. The solver must guess an some point. For example, you deduce that R3C5 must be 3 or 5, but since 3 leads to the first solution and 5 to the second one, there is no logical way to dec...
by Mephisto
Wed 11 Nov, 2020 7:18 am
Forum: Puzzle (incl. Sudoku) Rules & Tips
Topic: General Puzzle Rules & Definitions
Replies: 15
Views: 30073

Re: General Puzzle Rules & Definitions

"MUST be logically solvable" and "SHOULD have a unique solution" is a contradiction.
by Mephisto
Tue 10 Nov, 2020 2:45 pm
Forum: General Puzzle Discussions
Topic: PUZZLE METHODOLOGY
Replies: 3
Views: 8073

Re: PUZZLE METHODOLOGY

Google is your friend: Seacht for "How to solve ...", e.g. "How to solve Nurikabe"
by Mephisto
Thu 01 Oct, 2020 4:22 pm
Forum: Welcome!
Topic: Clickmazes relaunch
Replies: 5
Views: 3611

Re: Clickmazes relaunch

Andrea, check your email
by Mephisto
Thu 01 Oct, 2020 3:41 pm
Forum: Welcome!
Topic: Clickmazes relaunch
Replies: 5
Views: 3611

Re: Clickmazes relaunch

Hi! :-)

For some of your mazes I have Javascript programs – are you interested?
by Mephisto
Mon 07 Sep, 2020 2:31 pm
Forum: General Puzzle Discussions
Topic: Erich's Puzzle Palace
Replies: 1
Views: 2310

Erich's Puzzle Palace

http://www2.stetson.edu/~efriedma/puzzle/index.html is dead (404)

Does anyone know what happened to Erich's Puzzle Palace? Is there a new location? Has anyone valid contact data of Erich Friedman? (The old mail address is dead.)
by Mephisto
Sun 27 Jan, 2019 7:54 am
Forum: WPF Sudoku Technical Discussion forum
Topic: Sudoku Notes from Wei-Hwa Huang
Replies: 1
Views: 5108

Sudoku Notes from Wei-Hwa Huang

Wei-Hwa Huang wrote: »Some difficulty is that sometimes it's hard to distinguish between a Sudoku variant and a puzzle that simply uses a Latin square concept. So, I've restricted myself to cases where the puzzle seems clearly inspired by "Number Place" or "Sudoku".« http://www.mathpuzzle.com/Sudoku...
by Mephisto
Mon 07 Jan, 2019 11:36 am
Forum: WPF Sudoku Technical Discussion forum
Topic: READ ME FIRST: What is a Sudoku Committee
Replies: 28
Views: 32021

Re: READ ME FIRST: What is a Sudoku Committee

do we have to write a definition which include all previous wsc and gp puzzles
No! Obviously there is dissatisfaction with the scope of the WSC puzzles and this scope should be restricted. If we would consider all puzzles, only the status quo - with which some are dissatisfied - would freeze.
by Mephisto
Sun 06 Jan, 2019 6:20 pm
Forum: WPF Sudoku Technical Discussion forum
Topic: READ ME FIRST: What is a Sudoku Committee
Replies: 28
Views: 32021

Re: READ ME FIRST: What is a Sudoku Committee

A is Berlin, B is Stuttgart, C is Strasbourg. Do I have to conclude that Strasbourg is in Germany because the distance between Strasbourg and Stuttgart is much less than the distance between Stuttgart and Berlin, which is the capitale city of Germany? No, because there is a clear border between Ger...
by Mephisto
Mon 31 Dec, 2018 8:12 am
Forum: WPF Sudoku Technical Discussion forum
Topic: Greek-Latin Squares (Eulero)
Replies: 3
Views: 7723

Re: Greek-Latin Squares (Eulero)

It depends on the Sudoku (Variation) definition. You can interpret Eulero as 3D Sudoku with 2 layers: A number layer and a letter layer combined into one 2D diagram in which the layers influence each other. Each cell is part of 4 regions: numer rows, number columns, letter rows and letter columns. A...
by Mephisto
Mon 31 Dec, 2018 7:59 am
Forum: WPF Sudoku Technical Discussion forum
Topic: READ ME FIRST: What is a Sudoku Committee
Replies: 28
Views: 32021

Re: READ ME FIRST: What is a Sudoku Committee

Counter to what Mephisto is saying, it is not just that a Sudoku has 3 regional constraints in some places. I only quoted detuned and made my comments assuming this definition and questioned it. However, assuming your Sudoku definition, there are only two kinds of Sudoku:; regular and irregular. Or...
by Mephisto
Sun 30 Dec, 2018 6:46 pm
Forum: WPF Sudoku Technical Discussion forum
Topic: Zilina Sudoku [WSC 2009]
Replies: 1
Views: 4342

Re: Zilina Sudoku [WSC 2009]

The main controversial point with this example is that there are many cells in the grid which are only subject to row/column constraints, and there is no third regional constraint. And if you "overlay" a standard 3x3 grid: Is it a Sudoku then? Killer has also such an overlay, KenKen has not (but co...
by Mephisto
Sun 30 Dec, 2018 6:15 pm
Forum: WPF Sudoku Technical Discussion forum
Topic: READ ME FIRST: What is a Sudoku Committee
Replies: 28
Views: 32021

Re: READ ME FIRST: What is a Sudoku Committee

Thinking again: Now we come to the kernel of the poodle: If we agree on the rule "A Sudoku must have at least 3 regional constraints" then we can simply exclude many variants without further thinking. For example, we can exclude KenKen (but not KenKen with diaginals). A second simple rule may be: "A...
by Mephisto
Sun 30 Dec, 2018 6:00 pm
Forum: WPF Sudoku Technical Discussion forum
Topic: Greek-Latin Squares (Eulero)
Replies: 3
Views: 7723

Greek-Latin Squares (Eulero)

Eulero.jpg https://www.janko.at/Raetsel/Eulero/index.htm ➊ Enter a number from 1 to N and a letter from A to N into each cell of the diagram of size NxN ➋ so that each number and each letter occurs exactly once in each row and each column ➌ and each number-letter-combination occurs exactly once in ...
by Mephisto
Sun 30 Dec, 2018 5:52 pm
Forum: WPF Sudoku Technical Discussion forum
Topic: READ ME FIRST: What is a Sudoku Committee
Replies: 28
Views: 32021

Re: READ ME FIRST: What is a Sudoku Committee

impose the principle that a Sudoku variant should have some kind of 3rd regional constraint then it is very easy to say that kenken is not a Sudoku variant. Ok, then add the uniqueness of the numbers on the two diagonals to KenKen. Now you have a 3rd regional constraint. Is it a Sudoku yet? You hav...
by Mephisto
Sun 30 Dec, 2018 4:20 pm
Forum: WPF Sudoku Technical Discussion forum
Topic: READ ME FIRST: What is a Sudoku Committee
Replies: 28
Views: 32021

Re: READ ME FIRST: What is a Sudoku Committee

In your example, you make big steps and it is easy to draw a line between. So why should it always be the case that we should be unable to say no at each incremental adjustment of the rules? Short answer: Because the number of possible Sudoku variants is infinite, maybe nondenumerable. [think of a p...
by Mephisto
Sun 30 Dec, 2018 3:42 pm
Forum: WPF Sudoku Technical Discussion forum
Topic: Subset Sudoku
Replies: 2
Views: 5187

Re: Subset Sudoku

The main controversial aspect to this variant as far as I can see is the use of repeated symbols.
As in Star Battle Sudoku (there are 8 symbols, numbers from 1~7 and a star which must be used twice). [A good example to speak of symbols and not of numbers. SCNR.]
by Mephisto
Sun 30 Dec, 2018 3:32 pm
Forum: WPF Sudoku Technical Discussion forum
Topic: Ten Box Sudoku, Staircase Sudoku
Replies: 1
Views: 4400

Ten Box Sudoku, Staircase Sudoku

In these Sudoku variants there are "holes" in the diagram. Staircase Sudoku: Staircase.jpg https://www.janko.at/Raetsel/Sudoku-Varianten/024.a.htm Ten Box Sudoku: Ten-Box.jpg https://www.janko.at/Raetsel/Sudoku-Varianten/027.a.htm (It seems that I do not have the right to add a poll to a posting. de...
by Mephisto
Sun 30 Dec, 2018 3:01 pm
Forum: WPF Sudoku Technical Discussion forum
Topic: Subset Sudoku
Replies: 2
Views: 5187

Subset Sudoku

detuned asked for an example for a Sudoku (?) in which the latin rule is violated. What about Subset Sudoku? Subset-Sudoku.jpg See https://www.janko.at/Raetsel/Sudoku-Subset/index.htm Write numbers from 1 to N into the cells of the diagram, so that each number occurs exactly M times in each row, in ...
by Mephisto
Sun 30 Dec, 2018 2:55 pm
Forum: WPF Sudoku Technical Discussion forum
Topic: READ ME FIRST: What is a Sudoku Committee
Replies: 28
Views: 32021

Re: READ ME FIRST: What is a Sudoku Committee

Does the use of "we" imply that you would like to contribute more meaningfully to the committee's work? I do not know enough about this committee. Primarily, "we" are the members of this forum. But I'm open to be convinced to join. What are the convincing reasons to use the word "digit" over "numbe...
by Mephisto
Sun 30 Dec, 2018 2:39 pm
Forum: WPF Sudoku Technical Discussion forum
Topic: READ ME FIRST: What is a Sudoku Committee
Replies: 28
Views: 32021

Re: READ ME FIRST: What is a Sudoku Committee

however it is a pity to have too much overlap between the two competitions and as such a clear line needs to be drawn with regards to Sudoku variants. A clear line does not exist. This is one of the paradoxes that philosophers have discussed for a long time. The basic thesis is always the propositi...
by Mephisto
Sun 30 Dec, 2018 10:07 am
Forum: WPF Sudoku Technical Discussion forum
Topic: READ ME FIRST: What is a Sudoku Committee
Replies: 28
Views: 32021

Re: READ ME FIRST: What is a Sudoku Committee

First thoughts and basic questions: A classic Sudoku is not really a number puzzle, because it does not make use of the properties of numbers (Penao axioms). Digits (not numbers!) are simply used as signs. Instead of digits you can also use letters, colors or any symbols (star, circle, square, ...)....