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13 The Joker
   WSC and WPC 2017 -> WSC 2017 Instructions Booklet23 posts • Page 1 of 1 • 1
Hemant Kr Malani
Subject: Re: 13 The Joker @ 2017-10-02 11:06 PM (#23405 - in reply to #23401) (#23405) Top




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vopani - 2017-10-02 6:25 PM

Hemant Kr Malani - 2017-10-02 5:57 PM

2. Pencil Marks sudoku
The rule says that 'the joker may assume any of the given pencilmarks in the cell' but in r9c5 this is not true.
3. Non-Consecutive
Same here. The rule says that 'the joker may assume any value that is not consecutive to the digit in its adjacent cell' but this is not true in many cells for example 4 is consecutive to both 3&5 in box 4.

Can you please clarify which is correct--the rule or example?(I think the example)

2. In Pencilmarks, the digit '7' is the joker. R9C5 is a '7', the joker, and it can assume the value of '4' (or '5') to satisfy the pencilmark clue.


3. In Non Consecutive, the digit '4' is the joker. R5C2 is a '4', the joker, and it can assume the value of, say, '8' to satisfy non-consecutive constraint with the '3' to the left and it can assume the value of, say '2' (or even '8' again) to satisfy non-consecutive constraint with the '5' to the right.

The rule and example are both correct as per these descriptions.

Sorry I had some misunderstanding. Thanks for the clarification
forcolin
Subject: Re: 13 The Joker @ 2017-10-03 4:25 AM (#23410 - in reply to #23338) (#23410) Top





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8 Clock faces sudoku. I believe that the dot in the bottom left corner is of the wrong colour. In no way the joker can originate a clockwise sequence with the 2,4,6 placed in that way.
Also, why there is not white dot in the intersection R89 C23? in this case the 5 could be replacing a 7. Or in the intersection R78 C23, in this case the 5 replaces a 9.
This applies also for many other intersection where the joker is involved. In which sense the statement "All such dots are marked" should be interpreted?
vopani
Subject: Re: 13 The Joker @ 2017-10-03 9:16 AM (#23415 - in reply to #23410) (#23415) Top


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forcolin - 2017-10-03 4:25 AM

8 Clock faces sudoku. I believe that the dot in the bottom left corner is of the wrong colour. In no way the joker can originate a clockwise sequence with the 2,4,6 placed in that way.

Yes, it should be a black dot. Will get this fixed.
Thanks!

Also, why there is not white dot in the intersection R89 C23? in this case the 5 could be replacing a 7. Or in the intersection R78 C23, in this case the 5 replaces a 9.
This applies also for many other intersection where the joker is involved. In which sense the statement "All such dots are marked" should be interpreted?

For R89C23 and other similar 2x2 areas with the joker, the '5' at R8C2 assumes a value, of, say, '4' for that 2x2 area, and hence there is no dot, because it can neither be white nor black. So, the joker digit forces the digits to not be clockwise or anticlockwise, just like in other areas where it can fit clockwise or anticlockwise.
detuned
Subject: Re: 13 The Joker @ 2017-10-03 6:40 PM (#23434 - in reply to #23338) (#23434) Top




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Ok, so there might be two equally valid interpretations of the joker, the one which forcolin outlines and the one which Rohan has outlined. So it becomes a question of which interpretation takes precedence.

Perhaps we need a statement along the lines of “there exists a value the joker can take so that the dot or lack of dot works” whilst making clear that is also possible to choose other values which break the rule. Rereading this entire round, it strikes me that this definition of what a joker is has not been adequately described to remove the ambiguities in the rules. Could I suggest this is added as a round note please?
vopani
Subject: Re: 13 The Joker @ 2017-10-03 7:43 PM (#23436 - in reply to #23434) (#23436) Top


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detuned - 2017-10-03 6:40 PM

Ok, so there might be two equally valid interpretations of the joker, the one which forcolin outlines and the one which Rohan has outlined. So it becomes a question of which interpretation takes precedence.

Perhaps we need a statement along the lines of “there exists a value the joker can take so that the dot or lack of dot works” whilst making clear that is also possible to choose other values which break the rule. Rereading this entire round, it strikes me that this definition of what a joker is has not been adequately described to remove the ambiguities in the rules. Could I suggest this is added as a round note please?

We will review and get back on this.
jzverina
Subject: Re: 13 The Joker @ 2017-10-04 2:23 AM (#23444 - in reply to #23338) (#23444) Top


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Hi,
must be the joker always uniquely determinable? Example: in non-consecutive, if only numbers 4 and 5 break non-consecutivity (i.e. only consecutive pairs 45 appear in the grid), you can´t determine which of the digits is the joker. You need either 4 to touch 3 or 5 to touch 6 to uniquely identify the joker.
vopani
Subject: Re: 13 The Joker @ 2017-10-04 8:46 AM (#23449 - in reply to #23444) (#23449) Top


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jzverina - 2017-10-04 2:23 AM

Hi,
must be the joker always uniquely determinable? Example: in non-consecutive, if only numbers 4 and 5 break non-consecutivity (i.e. only consecutive pairs 45 appear in the grid), you can´t determine which of the digits is the joker. You need either 4 to touch 3 or 5 to touch 6 to uniquely identify the joker.

In all puzzles, the joker digit will be uniquely determinable, just like the IB examples.
So, the example you give will not happen.
vopani
Subject: Re: 13 The Joker @ 2017-10-06 10:27 AM (#23540 - in reply to #23436) (#23540) Top


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vopani - 2017-10-03 7:43 PM

detuned - 2017-10-03 6:40 PM

Ok, so there might be two equally valid interpretations of the joker, the one which forcolin outlines and the one which Rohan has outlined. So it becomes a question of which interpretation takes precedence.

Perhaps we need a statement along the lines of “there exists a value the joker can take so that the dot or lack of dot works” whilst making clear that is also possible to choose other values which break the rule. Rereading this entire round, it strikes me that this definition of what a joker is has not been adequately described to remove the ambiguities in the rules. Could I suggest this is added as a round note please?

We will review and get back on this.

We have added clarification in Clock Faces and Battenburg "The joker may also assume a value such that it satisfies the constraint of a dot / battenburg not being marked."

I hope that helps and makes it easier to understand.
TiiT
Subject: Re: 13 The Joker @ 2017-10-07 12:58 PM (#23556 - in reply to #23338) (#23556) Top




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Maybe it's easyer to understand if you think that a Joker can break any rules. If there is no battenburg sign and you know there is Joker in that 2x2 area, then it doesn't matter what the other digits are.
forcolin
Subject: Re: 13 The Joker @ 2017-10-08 10:17 PM (#23591 - in reply to #23556) (#23591) Top





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TiiT - 2017-10-07 12:58 PM

Maybe it's easyer to understand if you think that a Joker can break any rules. If there is no battenburg sign and you know there is Joker in that 2x2 area, then it doesn't matter what the other digits are.


this is not completely correct. At least half of the battenburg should be respected. In the example, it is obvious that the Battenburg is either 3 or 5 from the top corner. Hovever, R2C1 and R2C2 should still be one even number and one odd number, with the even number located below the joker.
forcolin
Subject: Re: 13 The Joker @ 2017-10-09 12:02 AM (#23595 - in reply to #23591) (#23595) Top





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forcolin - 2017-10-08 10:17 PM
......, with the even number located below the joker.


sorry, it's the other way round. the ODD number should be located under the joker
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