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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Sat Jul 17, 2010 5:25 am Post subject: Puzzle 10/07/17: XY+ |
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| Code: | +-----------------------+
| 8 . 6 | . . . | 9 . . |
| . 2 9 | . 6 . | . . . |
| 4 5 . | . . 9 | 8 6 . |
|-------+-------+-------|
| . . . | 5 . 1 | 2 . . |
| . 4 . | . . . | . . 8 |
| . . 8 | 4 . 3 | . 9 . |
|-------+-------+-------|
| 1 . 3 | 9 . . | . 8 2 |
| . . 4 | . . 8 | 6 1 . |
| . . . | . 4 . | 3 . 9 |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site
| Code: | after basics
+--------------------------------------------------------------+
| 8 37 6 | 37 1 45 | 9 2 45 |
| 37 2 9 | 8 6 45 | 57 3457 1 |
| 4 5 1 | 237 237 9 | 8 6 37 |
|--------------------+--------------------+--------------------|
| 369 369 7 | 5 8 1 | 2 34 346 |
| 235 4 25 | 6 9 27 | 1 357 8 |
| 256 1 8 | 4 27 3 | 57 9 567 |
|--------------------+--------------------+--------------------|
| 1 67 3 | 9 5 67 | 4 8 2 |
| 2579 79 4 | 237 237 8 | 6 1 57 |
| 2567 8 25 | 1 4 267 | 3 57 9 |
+--------------------------------------------------------------+
# 52 eliminations remain
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Sat Jul 17, 2010 10:34 am Post subject: |
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Another example of an m-wing with some work on one end..
| Quote: | gm-wing(37) (3=7)r1c2-(7=6)r7c2-(6=7)r7c6 - (7)r5c6=(7-3)r5c8=(3)r5c1; r2c1<>3
This seems to happen quite often? Instead of a bivalue creating a 3=7 link there is a short chain (or pseudocell) creating the same inference. |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sat Jul 17, 2010 1:20 pm Post subject: |
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A couple of fun, unusual moves......
| Quote: | An ANP(37=6) can be formed by combining the pseudocell (367)r59c1 from AUR25 in r59c13 with (37)r2c1. I am not sure how to notate but ...
ANP[AUR25(37)r59c13|(37)r2c1=AUR25(6)r59c13]r259c1-r9c6=r7c6-(6=7)r7c2*-(7=9)r8c2-r4c2=(9)r4c1; r4c1<>3, r8c2*<>7
Flightless AXY-wing3-57 vertex (37)r2c1, pincers (57)r2c7 & (35)r5c1 with fin (2)r5c1
If xy-wing is true: transport (5)r5c1-r89c1=r9c3-r9c8=(5)r8c9; r1c9<>5
If fin is true: (2)r5c1-(2=7)r5c6-r79c6=r8c45-(7=5)r8c9; r1c9<>5
ANP(25=3)r5c13-(3=7)r2c1-r2c7=r6c7-(7=2)r6c5; r5c6<>2 |
Ted |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sun Jul 18, 2010 10:34 am Post subject: |
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| excerpt that storm_norm wrote: | Unnamed Three Strong, Two Weak, Two Candidate Permutations
| Code: | = - = - =
A = A - (A=B) - B = B {1st A and last B in same house}
A = (A-B) = B - B = B {1st A and last B in same house}
A = A - A = (A-B) = B {reverse direction of above}
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The power of "L".
| Code: | +--------------------------------------------------------------+
| 8 37 6 | 37 1 45 | 9 2 45 |
| *37@ 2 9 | 8 6 45 | 57@ 3457 1 |
| 4 5 1 | 237 237 9 | 8 6 37 |
|--------------------+--------------------+--------------------|
| 369 369 7 | 5 8 1 | 2 34 346 |
| *235 4 25 | 6 9 27 | 1 *35-7 8 |
| 256 1 8 | 4 27 3 | 57@ 9 567 |
|--------------------+--------------------+--------------------|
| 1 67 3 | 9 5 67 | 4 8 2 |
| 2579 79 4 | 237 237 8 | 6 1 57 |
| 2567 8 25 | 1 4 267 | 3 57 9 |
+--------------------------------------------------------------+
# 52 eliminations remain
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Three strong inferences on two values with a transition in a bivalue cell: Norm's first pattern
| Code: | (7)r6c7 = r2c7 - (7=3)r2c1 - r5c1 = (3)r5c8 => r5c8<>7
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It's also a forcing chain constrained to a single value in each stream:
| Code: | (3): r2c1 - r5c1 = r5c8 => r5c8<>7 L-pattern
(7): r2c1 - r2c7 = r6c7 => r5c8<>7 L-pattern
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-also-
Three strong inferences on two values using an extension: Norm's third pattern
| Code: | turbot: (2)r6c1 = r6c5 - r5c6 = (2 )r9c6 => r9c1<>2
extension: ( -6)r9c6 = (6)r9c1 => r6c1<>6 !!!
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peterj
Joined: 26 Mar 2010
Posts: 974
Location: London, UK
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| Posted: Sun Jul 18, 2010 11:46 am Post subject: |
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| daj95376 wrote: |
| Code: | (7)r6c7 = r2c7 - (7=3)r2c1 - r5c1 = (3)r5c8 => r5c8<>7
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It's also a forcing chain constrained to a single value in each stream:
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Danny, that's very interesting!
For a start I am not used to seeing AIC where the elimination cell is the end of the chain with a strong link on one candidate - obviously thus implying the elimination on some other.
Occasionally I throw hard puzzles at SE and it comes out with a long list of mostly esoteric forcing chains  , most of which I would never find. But this pattern, certainly the first one, should be relatively easy to spot - no harder than a gm-wing anyway!
Peter |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sun Jul 18, 2010 12:32 pm Post subject: |
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Danny,
Appreciate the info.
Is it possible to get the link to the original post by storm_norm?
Ted |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sun Jul 18, 2010 12:47 pm Post subject: |
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| peterj wrote: | | daj95376 wrote: |
| Code: | (7)r6c7 = r2c7 - (7=3)r2c1 - r5c1 = (3)r5c8 => r5c8<>7
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It's also a forcing chain constrained to a single value in each stream:
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Danny, that's very interesting!
For a start I am not used to seeing AIC where the elimination cell is the end of the chain with a strong link on one candidate - obviously thus implying the elimination on some other.
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This might be a case where a discontinuous loop would be clearer:
| Code: | (7)r5c8 - r6c7 = r2c7 - (7=3)r2c1 - r5c1 = (3-7)r5c8
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Had there been a <3> in r6c7, then I would have added it to my elimination list. However, I suspect that a separate discontinuous loop would have been needed to show r6c7<>3.
Last edited by daj95376 on Sun Jul 18, 2010 1:02 pm; edited 1 time in total |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sun Jul 18, 2010 12:56 pm Post subject: |
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| tlanglet wrote: | Is it possible to get the link to the original post by storm_norm?
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I searched for it in three forums with no luck. I suspect that it was lost when the Players' Forums crashed and a year's worth of posts were lost. Here's my notes on his post.
| Code: | Three Strong, Two Weak, Inference Set:
= - = - =
xy-wing: (A=B) - (B=C) - (C=A)
w-wing: (A=B) - B = B - (B=A)
GM-wing: (A=B) - B = (B-A) = A
inv/xy: A = (A-B) = (B-C) = C {1st A and last C are in the same house}
fishy: A = A - A = A - A = A {1st and last A in the same house} loop
Cycle {includes 222 swordfish}
x-cycle: A = A - A = A - A = A {1st and last A not in the same house}
Danny's
skyscraper: A = (A - B) = B - B = B {1st A and last B in the same house}
extension
--------------------------------------
Two Strong, One Weak, Inference Set:
= - =
naked pair: (A=B) - (B=A) {both cells in same row/col/box} loop
Hidden Pair: A = (A-B) = B {the 1st A and the last B are in the same cell
all in the same row/col/box} loop
X-wing: A = A - A = A {1st A and last A in the same house} loop
Turbot Fish*: A = A - A = A {1st A and last A not in the same house}
*Skyscraper, 2-String Kite, and Empty Rectangle
===== ===== ===== ===== ===== ===== ===== ===== ===== ===== ===== ===== ===== =====
Unnamed Three Strong, Two Weak, Two Candidate Permutations
= - = - =
A = A - (A=B) - B = B {1st A and last B in same house}
A = (A-B) = B - B = B {1st A and last B in same house}
A = A - A = (A-B) = B {reverse direction of above}
---------------------
the xy-wing is a "named" three strong, two weak, three candidate chain
(A=B) - (B=C) - (C=A)
unnamed permutations including three candidates
(A=B) - (B=C) - C = C {A and last C in same house}
A = (A-B) = B - (B=C) {1st A and C in same house}
(A=B) - B = (B-C) = C {reverse direction of above}
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sun Jul 18, 2010 5:15 pm Post subject: |
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| Looking at the implications of the potential 23 DP in boxes 28; r1c69=54, r3c45<>7. |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Sun Jul 18, 2010 10:17 pm Post subject: |
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| Marty R. wrote: | | Looking at the implications of the potential 23 DP in boxes 28; r1c69=54, r3c45<>7. |
Marty,
Well, I have not been into the wine yet but it has been about 100+ F for several days and maybe that is my problem, but in any case I am not able to understand your post.
The condition, r1c69=54, results from completing basics. How does that influence the ADP23 in r38c45?
Also, what is the logic resulting in r3c45<>7
Ted |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sun Jul 18, 2010 11:09 pm Post subject: |
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| tlanglet wrote: | | Marty R. wrote: | | Looking at the implications of the potential 23 DP in boxes 28; r1c69=54, r3c45<>7. |
Marty,
Well, I have not been into the wine yet but it has been about 100+ F for several days and maybe that is my problem, but in any case I am not able to understand your post.
The condition, r1c69=54, results from completing basics. How does that influence the ADP23 in r38c45?
Also, what is the logic resulting in r3c45<>7
Ted |
Ted, I think it's safe to say that if r1c69=54 was there from basics, then I missed some basics. I guess that's why each of the possible DP killers led to those two cells being 45. When I tested the 7s, that led to an invalidity, thus my solution. I just tried the 7s again on Draw/Play and it too led to an invalidity.
Unfortunately, I make enough errors that I can't confidently say that one or more didn't creep in here.
| Quote: | | The condition, r1c69=54, results from completing basics. |
Danny missed that too, as his post-basics grid doesn't have those cells solved. |
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