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16 x 16 broken?

Submitted by: barclay

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The first to post today, good mAen to everybody!!!
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The island looks like a baseball cap..wonder where it is
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14:36 too long What rock is it?
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I found this one really tough. Had to make 4 guesses.

Cool picture.
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Hey, cms from nyc -- is that you?
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it is I! I usually can't do this till too late for anyone to care!
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I agree MB. Had to make 2 guesses,and both were bad.

I guess I am warmed up enough to attempt the ones in the newspaper now.
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Maen to all. This one lived up to its name. Found it to be very tough, but got through it. Have a nice day/night all!
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This puzzle is objectively much easier then the one from yesterday, or most of the recent ones.

A possible appraoch follows:

1) Start at 22 filled - the given puzzle. Unique Possibilities to 27. (UP 27).
2) Pair 57 at ab1 forbids 5 from a2,b3,d1 and forbids 7 from a2,b3,dgh1. More...
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Only step 5 of my proof is a little bit tricky. The establishment of non-native weak links is a mainstay of the proofs that I like to present. One can present the proof differently, but I find the non-native weak link approach very straighforward. In this case, it is clear that c2=6 forbids g6=1 More...
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Sorry about the poor grammar above!
... so it is likely there are puzzles which cannot use this approach.
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good mAen 11.23
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Steve - that hurts my blonde head. It's still only Sunday morning.
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17:15 with two guesses
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21:05 Much easier than yesterday's.
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Had to guess as usual. No good at tough. Is that the Bass Rock in east Lothian, Scotland?
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Unified Theory of Sudoku Solving:
Let A,B,C be any statement that will be exactly one of {True,False}.
The chain: C -- A == B -- C will solve every sudoku.

Note: The statements A,B,C include, but are not limited to:
Forbidding chains which meet the parameters (for example, A == B More...
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11:46 with a couple of guesses! Good mAen!
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Took 2 or 3 guesses on this one. Whew! I think I need a nap now. One day I will be doing toughs w/o guessing . . . I hope!
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Step 5 of my proof presented as a subset of the Unified Theory of Suddoku solving:
Consider the statement:{c6=36 and c4=36} replace this statement with:

{c6=6 == c6=3 -- c4=3 == c4=6}
now we have:
c6=1 == {c6=6 == c6=3 -- c4=3 == c4=6} -- c2=6 == c2=2 -- g2=2 == g6=2 forbids g6=1.

Hopefully this example clears up what I mean by this unified theory.
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BTW - this theory is nothing more than what gb teaches in his proof link below, except that I have generalized the 'arguments' or 'statements' a bit more widely. X cyles, Y cxycles, forbidding chains as they are commonly understood, ALS techniques, gaurdians, illegal-odd agons, singletons in a More...
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Steve, I would have to agree with Violette. Perhaps my rocket scientist husband could sit down with me and explain the intricasies of triangulating. I am very visual and would have to copy your solution and work it step by step...If I could understand the language. Thank God for 'guesses'
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Hi Sarahoz!
The language is explained in the link below - proofs. Also, I typically print out the puzzle when I look for eliminations, as it helps in the visualization process. I often draw the chains on the paper to ensure that I really understand it. I think, therefor, that the process I More...
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Hi Steve. I've never been able to get my head around forbidding chains. For instance, let's go back to #3 of your proof today. You say i5=1, what happened to the 3, why couldn't i5 just as well = 3? If so then i9 = 1. Where's the proof that i5 doesn't = 3? What am I missing here?
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48:27. Bleah.
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Is this Ayres Rock? Clear maEn to all.

This was a regular Tough, finally! 8:34 total minutes, 3:13 to set up, and 5:21 to solve.
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Hi Kaz - I do not say i5=1
I say i5=1 == something
This means i5=1 OR something
In the case of today,since the one's in row 5 are limited to two locations, either i5=1 OR a5=1
This is of course ALWAYS true for today's puzzle
== means OR. -- means NOT arg OR Not arg.
It is More...
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Further note:
If anyone chooses to understand forbidding chains, my proposed unified theory simple expands the list of statements that one uses in the chains to include ANY statement that is either true or false.

Thus, in the proof step three, it does not matter whether or not i5=1. It More...
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7.39 not bad for tough one. Not Ayers Rock! Not easily recogniseable.
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Slightly more explaining:
A == B -- C == D means:
Now, A is true or false.

If A is true, then whatever is forbidden by A is forbidden.
If A is false, then B must be true.
If B is true, then C must be false.
If C is false, then D must be More...
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Final note:
Often, it is misconstrued that A == B means exactly one is true. That may often be the case, but - the proof only requires that at least one of A, B be true - that both A and B cannot be false.
Similarily, A -- B only requires that at least one of A and B be false. It may be More...
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Hi Kaz again!
I think that if you follow my proof closely, you will see that I did not bother to do whatever you did to limit the one's in column i to just two locations, as that did not help. If you follow the proof precisely as written, then you should be able to see exactly what I did. That More...
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Hi Everyone,

Just added another requested feature. There is a new checkbox 'Grey out Used Numbers' which will indicate when you have used up all of a number.

Let me know what you think.

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Gath, Love the new feature!
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I would love the new feature, I think, especially in Easy and Medium where possibles aren't needed, but it doesn't seem to happen. I don't see anything changing.
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forgot to turn the timer on till after set up which is usually about 3mins plus 4.44 to finish
have a great day/night one and all
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Good maeN all

I truly believe Steve from Ohio deserves his own special comments page :o)

No offense meant
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Steve, I really appreciate your comments, especially your explanation yesterday. That one really had me stumped. Dave, I'm working on yours too.
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