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Tough Sudoku for 30/November/2006

                 
                 
                 
                 
                 
                 
                 
                 
                 

Choose a number, and place it in the grid above.

  1 2 3 4 5 6 7 8 9
Check out the latest post in the Sudoku Forum

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Submitted by: Gath

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she's saying please get out of my way i'm driving here!
'Well, isn't that special?'
20:34
'Cuter than the Michelin baby? Really?!'
my lips are sealed
mopsy
Such big eyes!
Gotta be baby Emily... she one of the cutest kids! Beautiful eyes, and a rosebud mouth!
'Look at me, mom!' She is beautiful.
She looks like she just ran into her first road hazzard
Hey, you should have asked me to say 'cheese'!
13:08 Get out of the way--she's coming through! Does that contraption have a turn indicator?
17:30 NO Quesses, I must be getting better at the 'tough's
For today's tough, rather than present the easiest proof, I thought perhaps to present two fc's that use 'multiple-chaining' for study. Both steps that use this technique are more transparently represented by matrices, but the concept is more easily understood as an fc, in my opinion.
Possible proof of tough sudoku of 11 30 06:
1) Start at 22 filled - the given puzzle. Unique Possibilities to 27 filled. (UP 27).
2a) Hidden pair 46 at a6b5 forbids a6=123,b5=1389
2b) Locked 1's at e456 forbids d56f45=1
2d) Locked 3's at df3 forbids f1=3
2e) Locked 2's at e46 More...
The depth of step 2f is 6, although the fc representation of the step uses 7 '==' {strong} links. The reason the depth is only 7 is that it uses the strong set of 1's in row 5, but those 1's are part of two fc links.
In a similar fashion, step 24 is depth 4, although it uses 5 strong links in the fc representation. Here, the 4's in row 8 and column f are considered.
Good afternoon to all! She's playing bumper cars, and you ought to see what she just did to her Dad!
Great Pic!!!
Anyone seen my hairbrush????????
Okay....ATTENTION...ATTENTION

All guesses for the competition have been lost!!!!

You will need to redo them if you wish to be a part of the competition.
Competition.....Competition.......Competition

Guess the weight and date of arrival of my Grandbaby. Click on 'competition' and be in the running for 6 months free membership that Gath has so graciously offered.
To all who wish to take part in the competition...

If you go to 'check out my page' after my name you will see a photo of Nicole at 37 weeks. This may help in your guess. Some of you may wish to revise your guess...lol....Maybe the 'BIG CRASH' was a good thing
no guesses 2:23
No guesses for me either on today's Tough. That doesn't happen very often! Woo...Hoo!!!
Were you expecting me to stop? Beautiful baby with nice big eyes to better see the world she lives in.
Yeah, sure, after a couple no guesses I'm right back at 3-4 guesses to solve this thing. How do you guys do it?? :\
Steve, I have a favor to ask. First, I'm a big fan of yours and of Clark. I think you guys are geniuses. I would appreciate if on each day's tough you could give some indication of how tough it is. I only try them if you say 'easy' of 'misplaced' to give me some idea of how tough it really is. If you say nothing, like today, I will stay away. Thanks and keep up the good work!
Beware! I am the red eye monster!
Hi all how you all doin
I'm sure its Emily too! Is it Jill?
Mmmm... what should I explore next? It does look like the beautiful Emily
One look and I thought Emily with all that hair, getting more beautiful each time we see her.
Nov. 3, 2007.
04/Nov/07 1:31 AM
Finished November 2006, except for 8, 10, and 24.
06/Nov/07 12:19 PM
the kraken way - UP=27
1.Kraken Row (1)ceh5 => (7)i1 UP=28
(1)c5 -c2 = (1-6)b2 = h2 - (6=7)i1
||
(1)e5 -(7)e5 = e4 - i4 = i1
||
(1)h5 -(8)h5 = (8-7)i4 = i1
2.Kraken Row (4)bdf8 => (4)a6 UP=81
(4)b8 -a9 = a6
||
(4)d8 -d6 = a6
||
(4)f8 -(6)f8 = g8 - g5 = b5 - (6=4)a6.
08/Jul/10 8:56 AM
Steve's original solution is of course better.
08/Jul/10 9:56 AM
that interlocked kraken on row/column of 4's is fascinating. The fact that a normal fc arrives at the hinge on a weak link (6-4)f8 creates two strong sets where a normal kraken creates one. Creates more possibility for productive sub-chaining by a factor of two!!
08/Jul/10 10:06 AM

SE=7.3
05/Sep/10 11:08 PM
a better way: UP27
1.aur(27)fh12:(6)h12=(5)f12-d2=(5-4)d6=(4-6)a6=a1 > -6i1
2.(6)b5=g5-g8=(6-4*)f8=[b8*=d8*-d6=e6] > -4b5, UP81
04/Feb/11 8:07 AM
18:49.
01/Jun/20 2:23 PM
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