| View previous topic :: View next topic |
| Author |
Message |
storm_norm
Joined: 18 Oct 2007
Posts: 1741
|
 Posted: Mon Jul 13, 2009 1:52 am Post subject: MM 1463 july 12, 2009 |
 |
|
| Code: | . 5 .|. . .|9 4 7
1 . 2|. 3 .|. . .
. . .|. 9 .|. . .
-----+-----+-----
. . .|1 . 9|. . .
2 . .|. . .|7 . 3
7 . .|6 . 3|. . 8
-----+-----+-----
. . .|. 8 .|. . .
. . .|. 1 .|4 . 2
. 6 1|. . .|. 5 . |
| Code: | .---------------.---------------.---------------.
| 38 5 38 | 2 6 1 | 9 4 7 |
| 1 9 2 | 4 3 7 | 68 68 5 |
| 46 7 46 | 5 9 8 | 23 23 1 |
:---------------+---------------+---------------:
| 56 38 38 | 1 7 9 | 256 26 4 |
| 2 1 69 | 8 5 4 | 7 69 3 |
| 7 4 59 | 6 2 3 | 15 19 8 |
:---------------+---------------+---------------:
| 49 2 47 | 39 8 5 | 13 137 6 |
| 59 38 57 | 39 1 6 | 4 378 2 |
| 38 6 1 | 7 4 2 | 38 5 9 |
'---------------'---------------'---------------' |
|
|
| Back to top |
|
 |
Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
|
| Posted: Mon Jul 13, 2009 3:21 am Post subject: brain |
|
|
An xy-chain eliminates the 4 in R3C1 and solves the puzzle.
Earl
A member of the chain gang. |
|
| Back to top |
|
|
tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
|
| Posted: Mon Jul 13, 2009 4:13 am Post subject: |
|
|
Norm, I found a one step solution using one of your "special" moves, but my notation is BAD.
| Quote: | xy-wing 57+9 with pivot 57 at r8c3, and yes, I mean a "+9" since the end result is that what I initially assumed was pincer became the cell value:
(5)r8c3 - (5=9)r6c3,
(7)r8c3 - (7)r8c8 which forms a hidden pair 38 in r8c8 & r9c7 that deletes 3 in r7c7 - (3=1)r7c7 - (1=5)r6c7 - (5=9)r6c3;
Thus, r6c3=9 if r8c3=5 or r8c3=7.
|
Ted
P.S. Norm I need to find one of your previous posts that used proper notation for this situation. Also, does this condition could have another name? |
|
| Back to top |
|
|
storm_norm
Joined: 18 Oct 2007
Posts: 1741
|
| Posted: Mon Jul 13, 2009 6:53 pm Post subject: |
|
|
| tlanglet wrote: | Norm, I found a one step solution using one of your "special" moves, but my notation is BAD.
| Quote: | xy-wing 57+9 with pivot 57 at r8c3, and yes, I mean a "+9" since the end result is that what I initially assumed was pincer became the cell value:
(5)r8c3 - (5=9)r6c3,
(7)r8c3 - (7)r8c8 which forms a hidden pair 38 in r8c8 & r9c7 that deletes 3 in r7c7 - (3=1)r7c7 - (1=5)r6c7 - (5=9)r6c3;
Thus, r6c3=9 if r8c3=5 or r8c3=7.
|
Ted
P.S. Norm I need to find one of your previous posts that used proper notation for this situation. Also, does this condition could have another name? |
Ted,
a couple of things.
a)you say "xy-wing 57+9 with pivot 57 at r8c3"... I think the use of the term "xy-wing" to describe the cell {5,7} is a bit of a misnomer
because...
| Code: | +--------+---------+-------+
| . . . | . 13 . | . . . |
| . 12 . | . . 23 | . . . |
| . . . | . . . | . . . |
+--------+---------+-------+ |
using the term xy-wing would accurately describe the relationship that the 3 cells in the above grid have with each other.
in the example in this thread, you are only referring to two cells which don't actually form a xy-wing. you instead are pointing out two cells which form a partial xy-wing.
in reality, all you are pointing out is that the cell {5,7} is the start of your net, that one of either 5 or 7 must be true. It has nothing to do with it being a part of a xy-wing.
-----
b) again, I think there is a misnomer concerning your use of the term "hidden pair" to describe the als (378) in r89c78.
| Code: | :---------------+---------------+---------------:
| 49 2 47 | 39 8 5 | 13 137 6 |
| 59 38 57 | 39 1 6 | 4 378 2 |
| 38 6 1 | 7 4 2 | 38 5 9 |
'---------------'---------------'---------------' |
if the 7 is removed from r8c8 then the locked set (38) remains, or "naked pair".
a hidden pair is something different.
| Code: | +-------------+-----------+---------+
| . . . | . . . | . . . |
| . 4567 4567 | . 678 14 | 78 . . |
| . . . | . . . | . . . |
+-------------+-----------+---------+ |
in the grid we have an almost hidden pair. the hidden pair (45)r2c23 would be true if the 4 in r2c6 is false.
this is not what we have in the example in this thread.
-----
the notation for your chain
(5=7)r8c3 - (7)r8c8 = (38)r89c78 - (3=1)r7c7 - (1=5)r6c7; r6c3 <> 5
-----
is this a valid BUG+3 deduction?
| Code: | .---------------.---------------.---------------.
| 38 5 38 | 2 6 1 | 9 4 7 |
| 1 9 2 | 4 3 7 | 68 68 5 |
| 46 7 46 | 5 9 8 | 23 *23 1 |
:---------------+---------------+---------------:
| 56 38 38 | 1 7 9 |25[6] *26 4 |
| 2 1 69 | 8 5 4 | 7 -69 3 |
| 7 4 59 | 6 2 3 | 15 19 8 |
:---------------+---------------+---------------:
| 49 2 47 | 39 8 5 | 13 [3]17 6 |
| 59 38 57 | 39 1 6 | 4 [3]78 2 |
| 38 6 1 | 7 4 2 | 38 5 9 |
'---------------'---------------'---------------' |
BUG+3[(6)r4c7 = (3)r78c8] - (3=2)r3c8 - (2=6)r4c8; r5c8 <> 6 |
|
| Back to top |
|
|
tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
|
| Posted: Mon Jul 13, 2009 7:09 pm Post subject: |
|
|
Thanks Norm for the comments.
I used the term xy-wing because I found the chain while looking for xy-wings, but I realize that what I found was not a "real" xy-wing. And yes, what I exposed was a "naked pair" not a "hidden pair"; I simply used the incorrect term.
I also looked at the potential BUG+3, but gave it up because I was not sure if it was valid; it has four 3s and my simple rule of three occurances in each house did not seem to apply.
Ted |
|
| Back to top |
|
|
daj95376
Joined: 23 Aug 2008
Posts: 3854
|
| Posted: Mon Jul 13, 2009 11:09 pm Post subject: |
|
|
[Edit: I was about to delete this reply, because it was incorrect, when Norm added a comment.]
Last edited by daj95376 on Mon Jul 13, 2009 11:26 pm; edited 1 time in total |
|
| Back to top |
|
|
storm_norm
Joined: 18 Oct 2007
Posts: 1741
|
| Posted: Mon Jul 13, 2009 11:23 pm Post subject: |
|
|
| what about the 3's in row 7 and 8. there are three 3's in each of those rows. |
|
| Back to top |
|
|
tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
|
| Posted: Tue Jul 14, 2009 12:31 am Post subject: |
|
|
| storm_norm wrote: | | what about the 3's in row 7 and 8. there are three 3's in each of those rows. |
Also three 3s in col8 which is ok, but what about the three 3s in col7 and the 3 in r9c7?
Ted |
|
| Back to top |
|
|
Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
|
| Posted: Sun Jul 19, 2009 5:18 am Post subject: |
|
|
is this a valid BUG+3 deduction?
| Code: |
.---------------.---------------.---------------.
| 38 5 38 | 2 6 1 | 9 4 7 |
| 1 9 2 | 4 3 7 | 68 68 5 |
| 46 7 46 | 5 9 8 | 23 *23 1 |
:---------------+---------------+---------------:
| 56 38 38 | 1 7 9 |25[6] *26 4 |
| 2 1 69 | 8 5 4 | 7 -69 3 |
| 7 4 59 | 6 2 3 | 15 19 8 |
:---------------+---------------+---------------:
| 49 2 47 | 39 8 5 | 13 [3]17 6 |
| 59 38 57 | 39 1 6 | 4 [3]78 2 |
| 38 6 1 | 7 4 2 | 38 5 9 |
'---------------'---------------'---------------' |
I looked at that and concluded, correctly or incorrectly, that it wasn't valid because there weren't three 6s in c7. If you remove the 6 from r4c7, then r2c7=6 and eliminations follow, there isn't a DP. |
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
