Simple Sudoku and Colors

bart · Posted: Thu Aug 11, 2005 9:56 am Post subject: Simple Sudoku and Colors

Hello

This is the sudoku (Expert) I'm working on:

copy/paste:

angusj · Site Admin

bart · Posted: Thu Aug 11, 2005 11:36 pm Post subject:

thanks!!

so easy... Embarassed

bart · Posted: Fri Aug 12, 2005 2:52 pm Post subject:

probably another simple solution, I just don't see it

from copy/paste

bart · Posted: Fri Aug 12, 2005 3:59 pm Post subject:

I've had the same problem in a few other puzzles but I think I've found the solution myself this time
is it because there are 2 blue's in the same block? must be

angusj · Site Admin

lennyh · Posted: Mon Aug 29, 2005 1:47 pm Post subject: Colors

I've been very much enjoying using Angus's lovely Simple Solver, but am confused by 1 aspect of the Colors technique. I believed this may have been explained earlier, but I'm still missing something.

Here goes: One of the rules associated with colors states "Whenever two cells in a conjugate chain have the same color and also share the same group, that color must be the 'false' color ..."

What does it mean to say that color is the 'false' color? Does it mean that the candidate can be removed from the cell with the 'false' color? But there are 2 cells within the group with the 'false' color. From which of these 2 'false' cells can the candidate be removed? Or can it be removed from both?

I expect I'm missing something rather basic here.

Thanks for any help.

bart · Posted: Mon Aug 29, 2005 2:14 pm Post subject: Re: Colors

lennyh · Posted: Mon Aug 29, 2005 3:36 pm Post subject:

Thanks for the helpful explanation, bart. I believe I understand it now. It never occurred to me that candidates associated with all the "false' color could be removed.

Lenny

lennyh · Posted: Mon Aug 29, 2005 10:21 pm Post subject: Still confused re colors

I thought I understood "Colors", but it's clear that I don't. I tried multicolors001.ss w/ Simple Sudoku and unfortunately am still confused.

At one point the puzzle candidates look like this -- filtering on 7

*** *** ***
*** *7* *7*
*** 77* 7**

**7 *** 77*
*** 7** *7*
**7 *7* ***

*** *** ***
*** *** ***
*** *** ***

Simple Solver hints that "MultiColors" is used to exclude candidates from
r3c4, r4c3, r5c8, and r6c6. And it appears to utilize 2 different chains to do this. After some study of this example, I'm a bit chagrined to admit that I don't understand colors at all. I'm not completely clear on how the chains are established, nor on the rules for excluding. Can someone clarify?

Thanks.

bart · Posted: Mon Aug 29, 2005 10:29 pm Post subject:

multicoloring is lot harder to understand

angusj · Site Admin

bart · Posted: Mon Aug 29, 2005 11:26 pm Post subject:

aah, now I understand
thanks

but this must be a more simple form of multicoloring?

angusj · Site Admin

lennyh · Posted: Tue Aug 30, 2005 1:49 am Post subject: Coloring

aj, thank you for the helpful explanation. Let me, if I may, ask a follow-up:

Consider your write-up, "Solving with Colors". In this write-up you describe 2 rules. The first (call it rule 1) begins "Whenever two cells in a conjugate chain have the same color..."

The second (rule 2) begins "Also, whenever a candidate outside the chain...".

Would you suggest that your helpful explanation in todays posting regarding multicolors001.ss is an example or particular case of either rule 1 or rule 2, or would you rather suggest that it is a separate rule -- perhaps specific to the multi-color consideration?

I'm trying to make it easier for someone like myself who is subject to brain pain when trying to understand the core logic behind a technique and would rather just apply a possibly more straight-forward rule.

Thanks for your consideration.

Lenny