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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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 Posted: Fri Feb 19, 2016 1:56 am Post subject: Helmut's Feb 18 Advanced |
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Enjoyed this one:
| Code: |
+-----------+-----------+-----------+
| 3 . 8 | . 4 . | . . 1 |
| . 1 . | . . . | . 2 . |
| . . . | 8 5 . | . . . |
+-----------+-----------+-----------+
| 5 . . | 9 1 . | 8 . . |
| . . 1 | . 3 . | 2 . . |
| . . 3 | . 7 4 | . . 6 |
+-----------+-----------+-----------+
| . . . | . 9 7 | . . . |
| . 4 . | . . . | . 5 . |
| 1 . . | . 2 . | 3 . 9 |
+-----------+-----------+-----------+
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Feb 19, 2016 2:57 am Post subject: |
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| Code: |
+------------+-------+---------+
| 3 5 8 | 2 4 9 | 7 6 1 |
| 49 1 49 | 7 6 3 | 5 2 8 |
| 6 27 27 | 8 5 1 | 4 9 3 |
+------------+-------+---------+
| 5 67 467 | 9 1 2 | 8 3 47 |
| 47 9 1 | 6 3 8 | 2 47 5 |
| 28 28 3 | 5 7 4 | 9 1 6 |
+------------+-------+---------+
| 28 3 5 | 1 9 7 | 6 48 24 |
| 79 4 279 | 3 8 6 | 1 5 27 |
| 1 678 67 | 4 2 5 | 3 78 9 |
+------------+-------+---------+
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Play this puzzle online at the Daily Sudoku site
| Quote: | | Coloring 7r5c1-r5c8=r4c9-r8c9=> -7r8c1 |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Fri Feb 19, 2016 6:32 am Post subject: |
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Marty,
Yes, I saw a skyscraper on 7 in C19.
But also, an XYZ-wing that takes 7 out of R9C3, leading to a BUG+1.
Or, even cooler, the pseudo-cell 48 in the 67 UR that makes an XY-wing 4-78 which makes eliminations in C89.
Keith |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Feb 19, 2016 8:05 am Post subject: |
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| keith wrote: | Marty,
Yes, I saw a skyscraper on 7 in C19.
But also, an XYZ-wing that takes 7 out of R9C3, leading to a BUG+1.
Or, even cooler, the pseudo-cell 48 in the 67 UR that makes an XY-Wing 4-78 which makes eliminations in C89.
Keith |
I don't understand anything about the pseudo cell XY-Wing.
Another way to get rid of the 7 in r9c3 other than the XYZ-Wing is to play the UR as a Type 6, which it is.
And the W-Wing on 67 sets up the Bug+1. |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Fri Feb 19, 2016 4:57 pm Post subject: |
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| Marty R. wrote: | | keith wrote: | Marty,
Yes, I saw a skyscraper on 7 in C19.
But also, an XYZ-wing that takes 7 out of R9C3, leading to a BUG+1.
Or, even cooler, the pseudo-cell 48 in the 67 UR that makes an XY-Wing 4-78 which makes eliminations in C89.
Keith |
I don't understand anything about the pseudo cell XY-Wing.
Another way to get rid of the 7 in r9c3 other than the XYZ-Wing is to play the UR as a Type 6, which it is.
And the W-Wing on 67 sets up the Bug+1. |
| Code: | +----------------+-------+-------------+
| 3 5 8 | 2 4 9 | 7 6 1 |
| 49 1 49 | 7 6 3 | 5 2 8 |
| 6 27 27 | 8 5 1 | 4 9 3 |
+----------------+-------+-------------+
| 5 67 (4)67 | 9 1 2 | 8 3 (47) |
| 47 9 1 | 6 3 8 | 2 4-7 5 |
| 28 28 3 | 5 7 4 | 9 1 6 |
+----------------+-------+-------------+
| 28 3 5 | 1 9 7 | 6 48 24 |
| 79 4 279 | 3 8 6 | 1 5 2-7|
| 1 67(8) 67 | 4 2 5 | 3 (78) 9 |
+----------------+-------+-------------+ |
Maybe you call it something different.
In the UR R4C3 is 4 and/or R9C2 is 8. This sets up pincers on 7 in R6C9 and R9C8.
Keith |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Feb 19, 2016 7:43 pm Post subject: |
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I don't know what to call it, but it provides the opening premise for a chain.
4r4c3=8r9c2-(8=7)r9c8-(7=2)r8c9-(2=4)r7c9=> -4r4c9. |
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dongrave
Joined: 06 Mar 2014
Posts: 568
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| Posted: Sat Feb 20, 2016 2:35 am Post subject: |
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| Marty R. wrote: |
| Quote: | | 7r5c1-r5c8=r4c9-r8c9=> -7r8c1 |
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Hi Marty, Don't the strong and weak links in your chain have to be just the opposite because if you end your chain with the weak link between r4c9 and r8c9, doesn't that imply that a strong link should exist between r8c9 and r8c1 - which is ruined by the 7 in r8c3? I'm probably just confused again - it seemed to me that it would have to be represented as 7r5c1=r5c8-r4c9=r8c9-r8c1; contradiction. This Eureka notation still confuses me sometimes. Thanks, Don. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Feb 20, 2016 5:18 am Post subject: |
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| That's not a standard chain that is usually notated Don. It's Simple Coloring, in which you need an even number of cells with the start and end cells having opposite "polarity." So the four cells I used are plus, minus, plus, minus and I tried to Eurekaize it. |
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dongrave
Joined: 06 Mar 2014
Posts: 568
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| Posted: Sat Feb 20, 2016 1:41 pm Post subject: |
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| Oh, I see! My chain was so similar to yours but mine was a strict chain so you had me wondering there! (4-7)r5c1=r8c1-r8c9=r4c9=>r4c23<>7. Hey! Last time I posted a chain w/ pincers on both ends I think you told me that most would begin the chain as '7r5c1=...' instead of '(4-7)r5c1' so I guess that would be the case here too? I thought maybe the '(4-7)' would accentuate the fact that it's saying 'If r5c1 is not a 7, then r4c9 is 7.' but it's not really necessary (or even preferred), is it? Thanks, Don. |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Feb 20, 2016 1:59 pm Post subject: |
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Don, I could've written it differently and, Perhaps, more conventionally as:
(7=4)r5c1-(4=7)r5c8-r4c9=r8c9=> -7r8c1 |
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dongrave
Joined: 06 Mar 2014
Posts: 568
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| Posted: Sat Feb 20, 2016 2:12 pm Post subject: |
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| Of course! I like it (because even I can understand it). |
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