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Clement
Joined: 24 Apr 2006 Posts: 864 Location: Dar es Salaam Tanzania

Posted: Sun Jul 20, 2014 5:14 pm Post subject: Free Press July 20, 2014 


Code: 
++++
 . . .  . 4 .  . . 1 
 1 . .  5 . .  . . . 
 9 . 6  . 2 .  7 4 . 
++++
 . . 8  . . .  . . 4 
 . 1 7  . . .  8 2 . 
 4 . .  . . .  3 . . 
++++
 . 7 5  . 9 6  2 . 8 
 . . .  . . 1  . . 7 
 6 . .  . 8 .  . . . 
++++

Play this puzzle online at the Daily Sudoku site 

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arkietech
Joined: 31 Jul 2008 Posts: 1754 Location: Northwest Arkansas USA

Posted: Sun Jul 20, 2014 8:18 pm Post subject: 


Code:  **
 7 28 23  36 4 39  569 568 1 
 1 a48 34  5 67 379  69 a68 2 
 9 5 6  1 2 8  7 4 3 
++
 2 3 8  67 67 5  1 9 4 
 5 1 7  9 3 4  8 2 6 
 4 6 9  8 1 2  3 7 5 
++
 3 7 5  4 9 6  2 1 8 
 8 9 b24 b23 5 1  46 b36 7 
 6 24 1  237 8 37  45 35 9 
**
(4=6)r2c28(6=4)r8c348 => 4r2c3,r9c2; ste 


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Marty R.
Joined: 12 Feb 2006 Posts: 5562 Location: Rochester, NY, USA

Posted: Sun Jul 20, 2014 11:31 pm Post subject: 


Code: 
++++
 7 28 23  36 4 39  569 568 1 
 1 48 34  5 67 379  69 68 2 
 9 5 6  1 2 8  7 4 3 
++++
 2 3 8  67 67 5  1 9 4 
 5 1 7  9 3 4  8 2 6 
 4 6 9  8 1 2  3 7 5 
++++
 3 7 5  4 9 6  2 1 8 
 8 9 24  23 5 1  46 36 7 
 6 24 1  237 8 37  45 35 9 
++++

Play this puzzle online at the Daily Sudoku site
If there's a patternbased move in there, it escaped me. XYChain.
(4=2)r8c3(2=3)r8c4(3=6)r8c8(6=8)r2c8(8=4)r2c2=>r9c2<>4 

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Clement
Joined: 24 Apr 2006 Posts: 864 Location: Dar es Salaam Tanzania

Posted: Mon Jul 21, 2014 12:22 pm Post subject: Free Press July 20, 2014 


It should be July 18, 2014 Code: 
++++
 7 28 23  36 4 39  569 568 1 
 1 b48 34  5 67 379  69 a68 2 
 9 5 6  1 2 8  7 4 3 
++++
 2 3 8  67 67 5  1 9 4 
 5 1 7  9 3 4  8 2 6 
 4 6 9  8 1 2  3 7 5 
++++
 3 7 5  4 9 6  2 1 8 
 8 9 d24  e23 5 1  46 f36 7 
 6 c24 1  237 8 37  45 35 9 
++++
 (6=8)r2c8(8=4)r2c2(4=2)r2c9r8c3=(23)r8c4=r8c8; r8c8<>6; stte. 

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dongrave
Joined: 06 Mar 2014 Posts: 264

Posted: Sat Jul 26, 2014 2:50 pm Post subject: 


Hi, could someone translate the notation in Marty's or Clement's solutions for me  or direct me to a link that explains it? Thanks in advance! Don. 

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Marty R.
Joined: 12 Feb 2006 Posts: 5562 Location: Rochester, NY, USA


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dongrave
Joined: 06 Mar 2014 Posts: 264

Posted: Sun Jul 27, 2014 12:01 am Post subject: 


Thanks Marty! Looks like good reading. Let me go over it until I understand it and I'll let you know if I have any questions. Don. 

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dongrave
Joined: 06 Mar 2014 Posts: 264

Posted: Sun Jul 27, 2014 3:49 pm Post subject: 


Hi again Marty! Well, I read it over and I understand it  but oh my God, who on earth designed this godawful notation? 'P=Q' is used to indicate that P and Q are not equal? What? Really? And then those nonintuitive contractions enclosed in parentheses? And if shortening expressions was their main concern, they why not replace r#c# with a1 > i9 (similar to chess notation). Is it just me? It seems like they went out of their way to make this as cryptic and confusing as possible. I guess I would have expected it to resemble the notation used in symbol logic or mathematical set theory! (I think I'll stick to English for now.) Thanks, Don. 

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Marty R.
Joined: 12 Feb 2006 Posts: 5562 Location: Rochester, NY, USA

Posted: Sun Jul 27, 2014 5:31 pm Post subject: 


Strong inference means both can't be false, i.e., one or the other must be true.
Weak inference means both can't be true.
Chains must be written with alternating strong and weak inferences. The last number in one term is the first number in the next term.
Clement's chain: (6=8)r2c8(8=4)r2c2(4=2)r2c9r8c3=(23)r8c4=r8c8; r8c8<>6
R2c8 must be 6 or 8. The number before the equal sign means if the cell is not that number. So in r2c8, if not 6 it must be 8. If 8, then r2c4 must be 4. Then r2c9 must be 2 if r2c2 is 4. If r2c9 is 2, then r8c3 is not 2 and r8c4 must be 2. Since r8c4 is 2, it can't be 3 and if it's not 3, then r8c8 must be 3.
So we've seen that if r2c8 is 8, then r8c8 must be 3. But if r2c8 is not 8, it must be 6, meaning r8c8 is 3. Thus, either way, r8c8 is 3 or unequal to 6.
Hope that's clear. 

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dongrave
Joined: 06 Mar 2014 Posts: 264

Posted: Fri Aug 01, 2014 2:36 am Post subject: 


Hi Marty, I take it from your response that it's just me that despises this Eureka notation. I like the way you made your point without even stating it. Don't others find this notation as cryptic and confusing as I did when they first see it? Oh well, if it's just me, then I'm going to go over this until it becomes second nature. Thanks again, Don. 

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Marty R.
Joined: 12 Feb 2006 Posts: 5562 Location: Rochester, NY, USA

Posted: Fri Aug 01, 2014 3:43 am Post subject: 


dongrave wrote:  Hi Marty, I take it from your response that it's just me that despises this Eureka notation. I like the way you made your point without even stating it. Don't others find this notation as cryptic and confusing as I did when they first see it? Oh well, if it's just me, then I'm going to go over this until it becomes second nature. Thanks again, Don. 
Well, Don, whether one loves Eureka or hates it, it's part of the game and those who don't know it are at a big disadvantage because it's the standard way that players describe their moves, the lingua franca of Sudoku, so to speak.
I learned Eureka years too late. I was getting sick of having to ask about someone's moves because I didn't understand the notation. Two years ago a fellow player who I've known for years put up with a lot of stupid questions and took the time to teach it to me for which I'm extremely grateful.
Quote:  Don't others find this notation as cryptic and confusing as I did when they first see it? 
Sure. One can't just look at it and understand it right off the bat; you're far from the only one. 

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keith
Joined: 19 Sep 2005 Posts: 3284 Location: near Detroit, Michigan, USA

Posted: Sat Aug 09, 2014 2:32 am Post subject: 


Uniqueness (BUG+3):
Code:  ++++
 7 28 23 C36 4 39 A569 B568 1 
 1 48 34  5 67 379  69 68 2 
 9 5 6  1 2 8  7 4 3 
++++
 2 3 8  67 67 5  1 9 4 
 5 1 7  9 3 4  8 2 6 
 4 6 9  8 1 2  3 7 5 
++++
 3 7 5  4 9 6  2 1 8 
 8 9 24 23 5 1  46 36 7 
 6 24 1 D237 8 37  45 35 9 
++++

A or B is 6, implying C is 3,
OR
D is 3,
taking out 3 in R8C4.
Keith 

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