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Unsolvable 5x5?
http://www.calcudoku.org/forum/viewtopic.php?f=17&t=818
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Author:  paulv66  [ Fri Aug 05, 2016 12:15 am ]
Post subject:  Unsolvable 5x5?

I got interrupted doing my first 5x5 yesterday and I got what seemed to me an unsolvable puzzle next time round. I've taken a screenshot of the puzzle. How do I go about posting it here?

Author:  jaek  [ Fri Aug 05, 2016 4:04 am ]
Post subject:  Re: Unsolvable 5x5?

paulv66 wrote:
I got interrupted doing my first 5x5 yesterday and I got what seemed to me an unsolvable puzzle next time round. I've taken a screenshot of the puzzle. How do I go about posting it here?

You can upload it to imgur.com without opening an account/setting up a profile, etc. I think there is an upload option in the nav options across the top of the page. Then you can post the link here.

Author:  paulv66  [ Fri Aug 05, 2016 6:10 am ]
Post subject:  Re: Unsolvable 5x5?

jaek wrote:
paulv66 wrote:
I got interrupted doing my first 5x5 yesterday and I got what seemed to me an unsolvable puzzle next time round. I've taken a screenshot of the puzzle. How do I go about posting it here?

You can upload it to imgur.com without opening an account/setting up a profile, etc. I think there is an upload option in the nav options across the top of the page. Then you can post the link here.


Thanks. I don't seem to be able to locate the nav options. Where exactly are they?

Author:  pnm  [ Fri Aug 05, 2016 8:00 am ]
Post subject:  Re: Unsolvable 5x5?

paulv66 wrote:
I got interrupted doing my first 5x5 yesterday and I got what seemed to me an unsolvable puzzle next time round. I've taken a screenshot of the puzzle. How do I go about posting it here?


You could also send me the screenshot and I'll add it to the post.

Author:  paulv66  [ Fri Aug 05, 2016 10:38 am ]
Post subject:  Re: Unsolvable 5x5?

pnm wrote:
paulv66 wrote:
I got interrupted doing my first 5x5 yesterday and I got what seemed to me an unsolvable puzzle next time round. I've taken a screenshot of the puzzle. How do I go about posting it here?


You could also send me the screenshot and I'll add it to the post.


Thanks Patrick

Do you have an email address I can send it to? I can't figure out how to send it as an attachment to a PM.

Author:  pnm  [ Fri Aug 05, 2016 11:27 am ]
Post subject:  Re: Unsolvable 5x5?

paulv66 wrote:
Do you have an email address I can send it to? I can't figure out how to send it as an attachment to a PM.

I'm guessing there's an email address somewhere on the main puzzle page [lol]

Author:  paulv66  [ Fri Aug 05, 2016 3:27 pm ]
Post subject:  Re: Unsolvable 5x5?

pnm wrote:
paulv66 wrote:
Do you have an email address I can send it to? I can't figure out how to send it as an attachment to a PM.

I'm guessing there's an email address somewhere on the main puzzle page [lol]


Sorry, not very alert today. I've send an email.

Thanks
Paul

Author:  pnm  [ Fri Aug 05, 2016 3:43 pm ]
Post subject:  Re: Unsolvable 5x5?

paulv66 wrote:
Sorry, not very alert today. I've send an email.


Thanks.

Here's the puzzle:

Image

and the reasoning:

paulv66 wrote:
My reasoning is as follows. The 3: cell must be 1,3. It follows from this that the 3- cell must be 2,5 and e5 must be 4. The\
40x cell must be 2,4,5. Therefore a4 and b4 must be 1,3. A4 is in a 12+ cell and therefore must be 3. But a5 and b5 must t\
hen be 4,5 which is impossible because e5 is 4. Where am I going wrong?


5 points for the first one to spot the flaw [tongue]

Author:  wjm  [ Fri Aug 05, 2016 4:19 pm ]
Post subject:  Re: Unsolvable 5x5?

Hello Patrick and paulv66!
The error in the enclosed analysis is that the 40x cage consists of 4 cells, not 3! Since there is already a 4 ar e4, one of the remaining 3 cells must have a 1 in it. This will allow a 4 to be placed at a4 with a 3 and a 5 at positions a5 and b5.
(It was always a given that it would be solvable!)
wjm

Author:  paulv66  [ Fri Aug 05, 2016 5:20 pm ]
Post subject:  Re: Unsolvable 5x5?

wjm wrote:
Hello Patrick and paulv66!
The error in the enclosed analysis is that the 40x cage consists of 4 cells, not 3! Since there is already a 4 ar e4, one of the remaining 3 cells must have a 1 in it. This will allow a 4 to be placed at a4 with a 3 and a 5 at positions a5 and b5.
(It was always a given that it would be solvable!)
wjm


Thanks! I'm such an idiot. I somehow or other got it into into my head that e5 was a single cell and the 40x was the other 3 cells. I also need to stop saying cell when I mean cage!

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