The New Sudoku Players' Forum

[Pat]

Hey Pat, do I get a pink elephant for
highlighting missing digits in some rows rather than duplicate digits

yes i prefer it that way
though the difference is rather minor

but i must apologize --
pink elephant is not in my vocabulary

[eleven]

Alternative solution:

Code: Select all

 *--------------------------------------------------*
 | 1    26   23   |*45   45   8    | 369  7    69   |
 | 4    9    7    | 1    6    3    | 5    8    2    |
 | 5    68   38   | 2    7    9    | 4    36   1    |
 |----------------+----------------+----------------|
 | 2    5    6    | 7    3    4    | 1    9    8    |
 | 8    1    4    | 56   9    2    | 7    36  *356  |
 | 7    3    9    | 8    15   16   | 2    4    56   |
 |----------------+----------------+----------------|
 | 6    7    12   |#349  8    5    | 39   12  #349  |
 | 3    4    18   | 69   2    16   | 689  5    7    |
 | 9    28   5    |#346  14   7    | 368  12  #346  |
 *--------------------------------------------------*

The UR 34 only leaves the 4 in r1c4 and the 3 in r5c9 in columns 49 (one of them must be true).
r5c9=3 -> r5c8=6 -> r5c4=5 -> r1c4=4
So in both cases we have r1c4=4.

[Cec]

"..However, by setting 6 at the start of the chain (r1c2)
the implications leave 3 at the end of the chain (r3c8)

how is that ??
which implications ??

please explain how you start with
r1c2 = 6
and reach the conclusion
r3c8 = 3

Here's my explanation or should I say error!

Cell r1c2 can only be 1 or 6. As stated by Steve above, if r1c2 does not contain 6 then that cell would be 2 which leads to r3c8=6.

Conversely, I similarly assumed that if r1c2 does not contain 2 then that cell would be 6. By "tracking" through the chain from A to K this leads to r3c8 being 3. hobiwan detected my error in cell H (r5c4) where I incorrectly implied r5c8=6 due to my ignoring the additional candidate 6 in r5c9. I assumed, incorrectly as it now seems, that because the chain included only bi-value cells, then any cells such as r5c9 which have more than two candidates could be ignored even though such cells could contain the "common" candidate 6, as in this case, which "bridges" the two cells H(r5c4) and J(r5c8).

Due to an annoying computer problem which has developed since upgrading my computer, I lose my typed individual replies to posts when trying to include these in the same thread. I would have liked to replied to all replies received so thanks again to all. The bottom line is that I still struggle with these notations and get frustrated because I still find the jargon difficult to follow.

Thanks udosuk for the following link which shows a similar multi-cell chain
http://forum.enjoysudoku.com/viewtopic.php?t=1131

As udosuk suggests, it seems I am mistaken the XY-Chain with another move such as the xy-ring.

Edited by Cec 8.40pm Wed 9 July. slash replaced dot after word com. thanks to eleven

Cec

[eleven]

The bottom line is that I still struggle with these notations and get frustrated because I still find the jargon difficult to follow.

You are not the only one
btw i would like to see the NL and AIC notation for my solution above.

Cec, please note, that you copied the link wrong. After "com" there should be a slash instead of the dot.

[daj95376]

[Withdrawn:]

[ronk]

i would like to see the NL and AIC notation for my solution above.

Pretty much just like you wrote ...

AUR(34)r79c49:(r1c4 =4|3= r5c9) -3- r5c8 -6- r5c4 -5- r1c4 ==>r1c4<>5

(4)r1c4 =AUR(34)r79c49= (3)r5c9 - (3=6)r5c8 - (6=5)r5c4 ==>r1c4<>5

[edit4: as eleven suggested, added AUR location and digts to notation]

[Glyn]

eleven Either of these should do the trick in Eureka notation, different players use slightly varied notations. My chain takes a slightly different route to set r1c4<>5. Hope it's of use anyway.

Code: Select all

UR (r79c49=34):
(4)r9c5-(4=5)r1c5
||
(3-5)r5c9=(5)r5c4

.

Code: Select all

(34)AUR r79c49
||
(4)r9c5-(4=5)r1c5
||
(3-5)r5c9=(5)r5c4


Here this Kraken always has the top option false at least one of the others must be true.

EDIT The notation is Eureka the Kraken is the structure leading to at least one free end being true. So not an AIC sorry for the confusion. The vertical || are not strong links.

[eleven]

Thanks for the notations.

What i am missing in ronk's are the cells of the AUR (of course no problem to add them).

I thought, Eureka and AIC notations were synonyms ... (or is the Kraken notation just a variety ?)

Concerning Glyn's route i dont see the link (4)r9c5=(3)r5c9 directly from the AUR (i would need the the AUR link (4)r9c5=(3)r79c7)

[ronk]

What i am missing in ronk's are the cells of the AUR (of course no problem to add them).

You're right, of course, so I've edited the post.

[Cec]

"...Cec, please note, that you copied the link wrong. After "com" there should be a slash instead of the dot.

Thanks eleven. I've corrected my above post.

Cec