The New Sudoku Players' Forum

[sweetbix]

Thanks ronk for that explanation of strong and weak. I’ve read it so many times but finally I think makes sense. I like Havard’s ideas on strong links too em. Do you think it's easier looking for coloring chains or strong links?

[ronk]

Do you think it's easier looking for coloring chains or strong links?

With coloring one alternately marks -- with colors, or with "A' and 'a', or with 'A+' and 'A-', etc. -- the nodes (cells) of a chain of strong links. Thus, there is little difference IMO.

[emm]

Edit : The post that was here has been deleted. In it, an invalid assumption led to an incorrect elimination which led to a sticky end. If anyone is interested in the errors you can still find them for they have been reposted by others - for the purposes of clarification - further on in this thread.

[TKiel]

Em,

I see how r4c1 can be excluded, but I'm puzzled as to how r4c5 relates to the strong links.

Code: Select all

 .  .  3 | .  .  C | . . .
 .  .  . | .  .  | | . . .
 A-------|----B  | | . . .
---------+-------|-+-----
 3* .  . | .  3* | | F . .
 .  .  3 | .  .  D | E . .
 3  .  3 | .  3  . | . . .
---------+---------+------
 .  .  . | .  .  . | . . .
 .  .  . | .  .  . | . . .
 .  .  . | .  .  . | . . .

Tracy

[ronk]

Colouring doesn’t get me far with the 3s in the 1st grid – but they fall easily to ‘strong links’.

Code: Select all

 .  .  3 | .  .  C | . . .
 .  .  . | .  .  | | . . .
 A-------|----B  | | . . .
---------+-------|-+-----
 3* .  . | .  3* | | F . .
 .  .  3 | .  .  D | E . .
 3  .  3 | .  3  . | . . .
---------+---------+------
 .  .  . | .  .  . | . . .
 .  .  . | .  .  . | . . .
 .  .  . | .  .  . | . . .

 .  .  A-|-------B | . . .
 .  .  . | .  .  . | . . .
 F  .  . | .  3* . | . . .
-|--------+--------+-----
 |  .  . | .  .  . | 3 . .
 |  .  3 | .  . /C | 3 . .
 E  .  3*| .  D/ . | . . .
---------+---------+------
 .  .  . | .  .  . | . . .
 .  .  . | .  .  . | . . .
 .  .  . | .  .  . | . . .

You are apparently guessing. Of your four eliminations, the only legitimate one is r4c1<>3.

[Havard]

Colouring doesn’t get me far with the 3s in the 1st grid – but they fall easily to ‘strong links’.

Code: Select all

 .  .  3 | .  .  C | . . .
 .  .  . | .  .  | | . . .
 A-------|----B  | | . . .
---------+-------|-+-----
 3* .  . | .  3* | | F . .
 .  .  3 | .  .  D | E . .
 3  .  3 | .  3  . | . . .
---------+---------+------
 .  .  . | .  .  . | . . .
 .  .  . | .  .  . | . . .
 .  .  . | .  .  . | . . .

 .  .  A-|-------B | . . .
 .  .  . | .  .  . | . . .
 F  .  . | .  3* . | . . .
-|--------+--------+-----
 |  .  . | .  .  . | 3 . .
 |  .  3 | .  . /C | 3 . .
 E  .  3*| .  D/ . | . . .
---------+---------+------
 .  .  . | .  .  . | . . .
 .  .  . | .  .  . | . . .
 .  .  . | .  .  . | . . .

You are apparently guessing. Of your four eliminations, the only legitimate one is r4c1<>3.

You obviously did not notice em's E-F link ronk... Two of the eliminations are valid. You can't take out R4C5 in the first one, and R3C5 in the second one. Thanks for your kind words em.

havard

[ronk]

You obviously did not notice em's E-F link ronk... Two of the eliminations are valid. You can't take out R4C5 in the first one, and R3C5 in the second one.

You apparently aren't paying attention Havard. Using coloring (or chaining strong links), you can't take out R4C1 without using the E-F link.

And using coloring, you can't take out R6C3 unless you first accept the invalid elimination of R4C5. IOW the C-D link isn't valid in the second one.

[Havard]

You obviously did not notice em's E-F link ronk... Two of the eliminations are valid. You can't take out R4C5 in the first one, and R3C5 in the second one.

You apparently aren't paying attention Havard. Using coloring (or chaining strong links), you can't take out R4C1 without using the E-F link.

And using coloring, you can't take out R6C3 unless you first accept the invalid elimination of R4C5. IOW the C-D link isn't valid in the second one.

Sorry, my bad. I did not realize the two examples was connected. I scanned them separately for eliminations.

havard

[emm]

Havard - you will have to pay more attention or I will be getting you into trouble!

Ron - you aren't a teacher are you? I have a theory about teachers. Anyway, it seems a bit harsh to say I was guessing even if I was wrong. I went through some exquisite processes to remove those 3s which I would refer to more as 'intuitive interpretation' or maybe 'creatively bending the rule' - that's kinder. Either way I stand corrected or I would do if it wasn't 2hrs past opening the Pinot and my relationship with the vertical wasn't compromised. As it is I am going to have to go and lie down corrected. I hope that will do.

[ronk]

I went through some exquisite processes to remove those 3s which I would refer to more as 'intuitive interpretation' or maybe 'creatively bending the rule' - that's kinder.

Sorry, I didn't mean to sound unkind, and that's why I wrote apparently guessing. However, solving a sudoku puzzle requires logic, not intuition. And it requires applying rules, not bending them.

Ron

[emm]

You don't need to apologise, Ron - I was being silly. Now I am contrite. I’m the one who needs to apologise for implying unkind things about teachers which was uncalled for - and unwarranted.