dailysudoku.com Forum Index dailysudoku.com
Discussion of Daily Sudoku puzzles
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Jul 23 VH

 
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Daily Sudoku puzzles
View previous topic :: View next topic  
Author Message
Clement



Joined: 24 Apr 2006
Posts: 1110
Location: Dar es Salaam Tanzania
PostPosted: Wed Jul 22, 2015 10:18 pm    Post subject: Jul 23 VH Reply with quote
Code:

+-------+-----------+---------+
| 8 6 3 | 1  57 4   | 57 9  2 |
| 5 4 9 | 6  27 23  | 8  37 1 |
| 1 7 2 | 9  58 38  | 4  35 6 |
+-------+-----------+---------+
| 9 8 6 | 5  3  27  | 1  27 4 |
| 7 2 1 | 4  9  6   | 3  8  5 |
| 3 5 4 | 28 1  278 | 27 6  9 |
+-------+-----------+---------+
| 2 3 5 | 7  6  1   | 9  4  8 |
| 6 1 8 | 3  4  9   | 25 25 7 |
| 4 9 7 | 28 28 5   | 6  1  3 |
+-------+-----------+---------+
XY-Wing pivoted in r2c8; r4c6<>2; stte
Also BUG+1; r6c6=2
Back to top
View user's profile Send private message AIM Address
bat999



Joined: 09 Jul 2015
Posts: 55
Location: UK
PostPosted: Thu Jul 23, 2015 12:29 am    Post subject: Reply with quote
Code:
.---------.---------------.-------------.
| 8  6  3 | 1   57   4    | c57   9   2 |
| 5  4  9 | 6   27   23   |  8    37  1 |
| 1  7  2 | 9   58  e38   |  4   d35  6 |
:---------+---------------+-------------:
| 9  8  6 | 5   3    27   |  1    27  4 |
| 7  2  1 | 4   9    6    |  3    8   5 |
| 3  5  4 | 28  1   a27-8 | b27   6   9 |
:---------+---------------+-------------:
| 2  3  5 | 7   6    1    |  9    4   8 |
| 6  1  8 | 3   4    9    |  25   25  7 |
| 4  9  7 | 28  28   5    |  6    1   3 |
'---------'---------------'-------------'
AIC: (7)r6c6 = r6c7 - (7=5)r1c7 - (5=3)r3c8 - (3=8)r3c6 => -8 r6c6; stte
Cool
Back to top
View user's profile Send private message
hughwill



Joined: 05 Apr 2010
Posts: 422
Location: Birmingham UK
PostPosted: Thu Jul 23, 2015 9:23 am    Post subject: Reply with quote
bat999 wrote:
Code:
.---------.---------------.-------------.
| 8  6  3 | 1   57   4    | c57   9   2 |
| 5  4  9 | 6   27   23   |  8    37  1 |
| 1  7  2 | 9   58  e38   |  4   d35  6 |
:---------+---------------+-------------:
| 9  8  6 | 5   3    27   |  1    27  4 |
| 7  2  1 | 4   9    6    |  3    8   5 |
| 3  5  4 | 28  1   a27-8 | b27   6   9 |
:---------+---------------+-------------:
| 2  3  5 | 7   6    1    |  9    4   8 |
| 6  1  8 | 3   4    9    |  25   25  7 |
| 4  9  7 | 28  28   5    |  6    1   3 |
'---------'---------------'-------------'
AIC: (7)r6c6 = r6c7 - (7=5)r1c7 - (5=3)r3c8 - (3=8)r3c6 => -8 r6c6; stte
Cool


For those in the know- don't you get the same result with a BUG+1
setting r6c6 to 2? (I have only a vague knowledge of such things...)

Hugh
Back to top
View user's profile Send private message
dongrave



Joined: 06 Mar 2014
Posts: 564
PostPosted: Thu Jul 23, 2015 5:10 pm    Post subject: Reply with quote
I see two 'standard' VH solutions. Clement's 37-2 XY-wing with pivot at r2c8 so r4c6<>2 and the 23-7 XY-wing with pivot at r2c6 so r4c8<>7.
Back to top
View user's profile Send private message
Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Thu Jul 23, 2015 5:52 pm    Post subject: Reply with quote
Code:

+-------+-----------+---------+
| 8 6 3 | 1  57 4   | 57 9  2 |
| 5 4 9 | 6  27 23  | 8  37 1 |
| 1 7 2 | 9  58 38  | 4  35 6 |
+-------+-----------+---------+
| 9 8 6 | 5  3  27  | 1  27 4 |
| 7 2 1 | 4  9  6   | 3  8  5 |
| 3 5 4 | 28 1  278 | 27 6  9 |
+-------+-----------+---------+
| 2 3 5 | 7  6  1   | 9  4  8 |
| 6 1 8 | 3  4  9   | 25 25 7 |
| 4 9 7 | 28 28 5   | 6  1  3 |
+-------+-----------+---------+

Play this puzzle online at the Daily Sudoku site

W=Wing (27) in b25 with SL 7 in c8 => -2r2c6.

Hugh, yes the BUG yields the same solution.
Back to top
View user's profile Send private message
Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Thu Jul 23, 2015 6:44 pm    Post subject: Reply with quote
bat999 wrote:
Code:
.---------.---------------.-------------.
| 8  6  3 | 1   57   4    | c57   9   2 |
| 5  4  9 | 6   27   23   |  8    37  1 |
| 1  7  2 | 9   58  e38   |  4   d35  6 |
:---------+---------------+-------------:
| 9  8  6 | 5   3    27   |  1    27  4 |
| 7  2  1 | 4   9    6    |  3    8   5 |
| 3  5  4 | 28  1   a27-8 | b27   6   9 |
:---------+---------------+-------------:
| 2  3  5 | 7   6    1    |  9    4   8 |
| 6  1  8 | 3   4    9    |  25   25  7 |
| 4  9  7 | 28  28   5    |  6    1   3 |
'---------'---------------'-------------'
AIC: (7)r6c6 = r6c7 - (7=5)r1c7 - (5=3)r3c8 - (3=8)r3c6 => -8 r6c6; stte
Cool


Bat, I don't know what's going on with that chain. Normally when you start out with -7, the chain ends with =7, creating pincers on 7. In this case, the chain says if r6c6<>7, then r3c6=8. I can't see an elimination there. Now let's look at the opening term's opposite, i.e. r6c=7.which, does indeed result in r6c6-8.
The reader can't see that conclusion from the chain so he has to assume the opening term's opposite and carry things out to see a conclusion.

I'd look for a more straightforward XY-Chain, Such as, (3=2)r2c6-(2=7)r4c6-(7=2)r4c8 -(2=5)r8c8-(5=3)r3c8=>-3r2c8,r3c6
Back to top
View user's profile Send private message
bat999



Joined: 09 Jul 2015
Posts: 55
Location: UK
PostPosted: Thu Jul 23, 2015 7:34 pm    Post subject: Reply with quote
Marty R. wrote:
... In this case, the chain says if r6c6<>7, then r3c6=8. I can't see an elimination there...

Code:
.---------.---------------.-------------.
| 8  6  3 | 1   57   4    | c57   9   2 |
| 5  4  9 | 6   27   23   |  8    37  1 |
| 1  7  2 | 9   58  e38   |  4   d35  6 |
:---------+---------------+-------------:
| 9  8  6 | 5   3    27   |  1    27  4 |
| 7  2  1 | 4   9    6    |  3    8   5 |
| 3  5  4 | 28  1   a27-8 | b27   6   9 |
:---------+---------------+-------------:
| 2  3  5 | 7   6    1    |  9    4   8 |
| 6  1  8 | 3   4    9    |  25   25  7 |
| 4  9  7 | 28  28   5    |  6    1   3 |
'---------'---------------'-------------'
AIC: (7)r6c6 = r6c7 - (7=5)r1c7 - (5=3)r3c8 - (3=8)r3c6 => -8 r6c6; stte
Cool

Hi
It's saying...
If r6c6=7 then r6c6<>8 (obviously).
If r6c6<>7 then r3c6=8 (which would kill an 8 in r6c6).

Either way, r6c6 can't be an 8.
=> -8 r6c6
Cool
Back to top
View user's profile Send private message
Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Thu Jul 23, 2015 9:08 pm    Post subject: Reply with quote
Bat, I see what you're doing and agree with the conclusion. I saw the way the chain started and was expecting to see a 7 in the final term to create the pincers, so that is why I replied. I guess I was a little confused and it just took me a little while. Sorry, I overreacted.
Back to top
View user's profile Send private message
bat999



Joined: 09 Jul 2015
Posts: 55
Location: UK
PostPosted: Thu Jul 23, 2015 10:11 pm    Post subject: Reply with quote
Marty R. wrote:
... overreacted...
No problem. Smile
It's good for you to ask the question, made me check again that I hadn't goofed. Wink
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Daily Sudoku puzzles All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group