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Puzzle 11/07/19: ~ XY
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daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Tue Jul 19, 2011 10:57 pm Post subject: Puzzle 11/07/19: ~ XY

Code:

+-----------------------+
| 4 8 1 | 9 . . | . . . |
| 9 6 . | 2 . . | . . . |
| 5 . 3 | . 8 . | 9 . . |
|-------+-------+-------|
| 8 9 . | 3 2 . | . . 4 |
| . . 2 | 5 9 . | . . . |
| . . . | . . . | . . 9 |
|-------+-------+-------|
| . . 6 | . . . | 4 . 8 |
| . . . | . . . | . 6 3 |
| . . . | 6 . 9 | 1 2 7 |
+-----------------------+

Play this puzzle online at the Daily Sudoku site

tlanglet

Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

Posted: Wed Jul 20, 2011 4:35 am Post subject:

My first pass was three steps.........

Quote:

w-wing (16)r3c9+r4c6 GSL(1)r234c8; r3c6<>6
w-wing (14)r2c5+r8c2 sl (3)r9c25; r8c5<>1
BUG+1 ; r8c4=7

Ted

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Wed Jul 20, 2011 4:44 am Post subject:

Does this chain count as Remote Pairs based on Keith's post here? http://www.dailysudoku.co.uk/sudoku/forums/viewtopic.php?t=2030 I used this chain as Remote Pairs, but don't know if it's valid or a lucky mistake: 16-67-16-16. If not valid, then I go back to the drawing boards. Remote Pairs (16); r3c6<>16 XYZ-Wing (147); r8c4<>1 BUG+2

Luke451

Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California

Posted: Wed Jul 20, 2011 5:57 am Post subject:

Marty R. wrote:

Does this chain count as Remote Pairs.....?

Code:

*--------------------------------------------------------------------*
| 4 8 1 | 9 3567 3567 | 67 37 2 |
| 9 6 7 | 2 134 13 | 38 1348 5 |
| 5 2 3 | 147 8 167 | 9 147 #16 |
|----------------------+----------------------+----------------------|
| 8 9 5 | 3 2 #16 |*67 *17 4 |
| 167 17 2 | 5 9 4 | 38 38 #16 |
| 16 3 4 | 178 167 1678 | 2 5 9 |
|----------------------+----------------------+----------------------|
| 127 157 6 | 17 1357 12357 | 4 9 8 |
| 127 147 9 | 1478 147 1278 | 5 6 3 |
| 3 45 8 | 6 45 9 | 1 2 7 |
*--------------------------------------------------------------------*

Cool, Marty, why not? The (16) in r4c78 can be looked at as the missing link, a psuedo-cell.

ronk

Joined: 07 May 2006
Posts: 398

Posted: Wed Jul 20, 2011 11:51 am Post subject:

Luke451 wrote:

Marty R. wrote:

Does this chain count as Remote Pairs.....?

Code:

Cool, Marty, why not? The (16) in r4c78 can be looked at as the missing link, a psuedo-cell.

I believe Marty R is referring to ...

Code:

(1=6)r3c9 - (6)r5c9 = (6)r4c7 - (6=1)r4c6 ==> r3c6<>1
(6)r3c9 = (6)r5c9 - (6)r4c7 = (6)r4c6 ==> r3c6<>6

... a co-located w-wing and x-chain (a kite in this case).

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Wed Jul 20, 2011 5:45 pm Post subject:

Please forgive my denseness, but forgetting about pseudo cells, W-Wings and chains, can 16-67-16-16 be played as Remote Pairs the same as if it were 16-16-16-16?

ronk

Joined: 07 May 2006
Posts: 398

Posted: Wed Jul 20, 2011 7:57 pm Post subject:

Marty R. wrote:

... can 16-67-16-16 be played as Remote Pairs ...?

Only if the chain of cells holding those bivalues meet a requrement you haven't stated.

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Wed Jul 20, 2011 9:30 pm Post subject:

ronk wrote:

Marty R. wrote:

... can 16-67-16-16 be played as Remote Pairs ...?

Only if the chain of cells holding those bivalues meet a requrement you haven't stated.

Sorry, I'm not understanding. Embarassed

Luke451

Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California

Posted: Wed Jul 20, 2011 10:38 pm Post subject:

ronk wrote:

Luke451 wrote:

Marty R. wrote:

Does this chain count as Remote Pairs.....?

Code:

Cool, Marty, why not? The (16) in r4c78 can be looked at as the missing link, a psuedo-cell.

I believe Marty R is referring to ...

Code:

(1=6)r3c9 - (6)r5c9 = (6)r4c7 - (6=1)r4c6 ==> r3c6<>1
(6)r3c9 = (6)r5c9 - (6)r4c7 = (6)r4c6 ==> r3c6<>6

... a co-located w-wing and x-chain (a kite in this case).

A remote pair pattern is two co-located x-chains. Marty's pattern is also two co-located x-chains, both kites.

Code:

(6)r3c9 = (6)r5c9 - (6)r4c7 = (6)r4c6 ==> r3c6<>6
(1)r3c9 = (1)r5c9 - (1)r4c8 = (1)r4c6 ==> r3c6<>1

Granted, one of the bivalue cells is stretched over two cells, but it still acts exactly like remote pairs. I don't know if "psuedo-cell" is the correct term for that, but it seemed appropriate at the time.

Marty, I don't see the need to include the 7 in the pattern at all.

Kdelle

Joined: 20 Mar 2008
Posts: 59
Location: Hudson, NH

Posted: Wed Jul 20, 2011 10:53 pm Post subject:

Marty R. wrote:

ronk wrote:

Marty R. wrote:

... can 16-67-16-16 be played as Remote Pairs ...?

Only if the chain of cells holding those bivalues meet a requrement you haven't stated.

Sorry, I'm not understanding. Embarassed

Marty,

I looked at the 16-16-67-16 as a chain (even number of cells)....strong links on 6.....so in any cell that sees both ends of the chain, the 6 can be eliminated. Is that what you mean?

Ronk...Did you mean that Marty should have stated the "strong link on 6" as a requirement of the bivalves?

Kathy

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Thu Jul 21, 2011 12:28 am Post subject:

Marty R. wrote:

Does this chain count as Remote Pairs based on Keith's post here?

http://www.dailysudoku.co.uk/sudoku/forums/viewtopic.php?t=2030

I used this chain as Remote Pairs, but don't know if it's valid or a lucky mistake: 16-67-16-16. If not valid, then I go back to the drawing boards.

Yes. Your endpoint cells and the strong links on <6> qualify as a general Remote Pair.

Quote:

Please forgive my denseness, but forgetting about pseudo cells, W-Wings and chains, can 16-67-16-16 be played as Remote Pairs the same as if it were 16-16-16-16?

No. The contents of the cells alone is insufficient information. You must also know that there are three strong links present for <6>.

Luke451: Ron's two chains are equivalent to Keith's definition of a general Remote Pair using four cells. The give-away is the identical bivalue cells as endpoints of an X-Chain where all inferences are strong links. In this case:

Code:

[r4] 16-67 is a strong link on <6>
[b6] 67-16 is a strong link on <6>
[c9] 16-16 is a strong link on <6>

-alternately, a second example using the same endpoint cells-

[r4] 16-17 is a strong link on <1>
[b6] 17-16 is a strong link on <1>
[c9] 16-16 is a strong link on <1>

Last edited by daj95376 on Thu Jul 21, 2011 12:52 am; edited 1 time in total

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Thu Jul 21, 2011 12:46 am Post subject:

Quote:

Quote:
Please forgive my denseness, but forgetting about pseudo cells, W-Wings and chains, can 16-67-16-16 be played as Remote Pairs the same as if it were 16-16-16-16?

No. The contents of the cells alone is insufficient information. You must also know that there are three strong links present for <6>.

Thanks Danny, that's the reassurance that I needed.

ronk

Joined: 07 May 2006
Posts: 398

Posted: Thu Jul 21, 2011 12:58 am Post subject:

Luke451 wrote:

A remote pair pattern is two co-located x-chains.

I believe that's the first time I've seen that definition for a "remote pair." Pseudo remote pair would be more appropriate ... for that and what [edit: keith termed] a general remote pair.

This forum seems to be the home for ad hoc definitions of the "remote pair." Something in the air maybe.

[edit: add the below]

Kdelle wrote:

Did you mean that Marty should have stated the "strong link on 6" as a requirement of the bivalves?

Yes, daj95376 phrased it well in a post above.

Last edited by ronk on Thu Jul 21, 2011 2:42 pm; edited 1 time in total

Luke451

Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California

Posted: Thu Jul 21, 2011 2:35 am Post subject:

ronk wrote:

This forum seems to be the home for ad hoc definitions of the "remote pair." Something in the air maybe.

They don't call me Mr. Pseudoku fer nuthin'... Very Happy

I agree. A remote pair is a remote pair. Variations being called "remote pairs" can lead to confusion.

These days I don't see remote pairs anyways, but oddagons.

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Thu Jul 21, 2011 3:52 am Post subject:

Quote:

Ronk...Did you mean that Marty should have stated the "strong link on 6" as a requirement of the bivalves?

No mollusks here Kathy, with or without requirements. Laughing

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Thu Jul 21, 2011 6:21 am Post subject:

ronk wrote:

... for that and what daj95376 calls a general remote pair.

This forum seems to be the home for ad hoc definitions of the "remote pair." Something in the air maybe.

It's not what ***I*** call it, it's what Keith called it in a Dec 29, 2007 post.

ronk

Joined: 07 May 2006
Posts: 398

Posted: Thu Jul 21, 2011 2:46 pm Post subject:

daj95376 wrote:

It's not what ***I*** call it, it's what Keith called it in a Dec 29, 2007 post.

Thanks, I stand corrected and have edited that post. I thought of you because you've probably used the 'general remote pair' term more than anyone else recently.

susume

Joined: 13 May 2011
Posts: 36
Location: Southeastern US

Posted: Fri Jul 22, 2011 4:27 am Post subject:

skyscraper (6)r3c9=r3c6-r4c6=r4c7 => r5c9<>6=1

Code:

+---------+---------------+--------+
| 4 8 1 | 9 56 56 | 7 3 2 |
| 9 6 7 | 2 14 3 | 8 14 5 |
| 5 2 3 | 14 8 7 | 9 14 6 |
+---------+---------------+--------+
| 8 9 5 | 3 2 1 | 6 7 4 |
| 6 7 2 | 5 9 4 | 3 8 1 |
| 1 3 4 | 78 67 68 | 2 5 9 |
+---------+---------------+--------+
| 27 15 6 | 17 3 25 | 4 9 8 |
| 27 14 9 | 48+17 17+4 28 | 5 6 3 |
| 3 45 8 | 6 45 9 | 1 2 7 |
+---------+---------------+--------+

BUG+3 (17)r8c4=(4)r8c5-(4=5)r9c5-(5=6)r1c5-(6=7)r6c5-(7=8)r6c4 => r6c4=8

peterj

Joined: 26 Mar 2010
Posts: 974
Location: London, UK

Posted: Fri Jul 22, 2011 8:15 am Post subject:

susume, that's a real interesting BUG move! Don't often see this sort of move and still being able to notate it as a chain.

Some would use a "quantum naked pair" notation to make the elimination clearer in the case of (17)r8c4 i.e.

Code:

qnp(17)r78c4=(4)r8c5 ...

Fwiw the chain part can just be extended to make the elimintation without the uniqueness constraint if you wish....

Code:

(7=1)r7c4 - (1=5)r7c2 - (5=4)r9c2 - (4=5)r9c5 - (5=6)r1c5 - (6=7)r6c5 ; r6c4<>7=8

ronk

Joined: 07 May 2006
Posts: 398

Posted: Fri Jul 22, 2011 10:39 am Post subject:

susume wrote:

Code:

BUG+3 (17)r8c4=(4)r8c5-(4=5)r9c5-(5=6)r1c5-(6=7)r6c5-(7=8)r6c4 => r6c4=8

Pretty, but don't forget that eliminations can be made in the cells with extra candidates.

BUG+3:(17)r78c4=(4)r8c5 ==> r8c4<>4, r8c5<>17

The naked pair (17)r78c4 is not quantum because it is in two cells rather than three.

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