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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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 Posted: Wed May 31, 2017 5:29 am Post subject: May 31 VH |
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| Code: |
+--------------+----------+---------------+
| 1 4 238 | 9 27 6 | 237 5 2378 |
| 7 5 29 | 3 4 8 | 29 6 1 |
| 268 89 23689 | 17 127 5 | 4 279 2378 |
+--------------+----------+---------------+
| 68 2 678 | 4 38 1 | 379 79 5 |
| 4 3 17 | 56 56 9 | 127 8 27 |
| 9 18 5 | 2 38 7 | 136 4 36 |
+--------------+----------+---------------+
| 25 19 4 | 8 19 3 | 2567 27 267 |
| 3 6 28 | 57 57 4 | 28 1 9 |
| 58 7 19 | 16 169 2 | 58 3 4 |
+--------------+----------+---------------+
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Play this puzzle online at the Daily Sudoku site
| Quote: | took me 2 steps
1) XY-Wing (29-8)=> -8r13c3
2) X-Wing (2)r28=> -2r13c3,r157c7 |
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ZeroAssoluto
Joined: 05 Feb 2017
Posts: 871
Location: Rimini, Italy
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| Posted: Wed May 31, 2017 7:15 am Post subject: |
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Hi everyone,
I also in two steps
| Quote: | X-Wing with number 2 in r28c37 and -2 in r1c37, r3c3, r5c7 and r7c7;
W-Wing with 3,8 in r3c9 and r6c5 connected by number 8 in r36c2 and -3 in r6c9. |
Ciao Gianni |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Wed May 31, 2017 8:17 am Post subject: |
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Hi everyone
X wing 2 ( line 2 and line 8 )-->-2R1C3 -2R3C3 -2R7C7 -2R1C7 -2R5C7
AIC R8C3<8>R9C1=8=>R4C1<8>R4C1=6=>R4C3<6>R3C3=6=>R3C3<8>-8 R3C3
AIC R8C3<8>R9C1=8=>R4C1<8>R4C1=6=>R4C3<6>R3C3=6=>R3C3<3>R1C3=3=>R1C3<8>-8 R1C3
Ciao a tutti
Paolo |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Wed May 31, 2017 3:34 pm Post subject: |
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Hi everyone
Sorry for mistakes on formulas.
Correct formulas
X wing 2 ( line 2 and line 8 )-->-2R1C3 -2R3C3 -2R7C7 -2R1C7 -2R5C7
AIC R8C3≠8=>R9C1=8=>R4C1≠8=>R4C1=6=>R4C3≠6=>R3C3=6=>R3C3≠8=>-8 R3C3
AIC R8C3≠8=>R9C1=8=>R4C1≠8=>R4C1=6=>R4C3≠6=>R3C3=6=>R3C3≠3=>R1C3=3=>R1C3≠8=>-8 R1C3
Ciao a tutti
Paolo |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Wed May 31, 2017 5:45 pm Post subject: |
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+--------------+----------+---------------+
| 1 4 238 | 9 27 6 | 237 5 2378 |
| 7 5 29 | 3 4 8 | 29 6 1 |
| 268 89 23689 | 17 127 5 | 4 279 2378 |
+--------------+----------+---------------+
| 68 2 678 | 4 38 1 | 379 79 5 |
| 4 3 17 | 56 56 9 | 127 8 27 |
| 9 18 5 | 2 38 7 | 136 4 36 |
+--------------+----------+---------------+
| 25 19 4 | 8 19 3 | 2567 27 267 |
| 3 6 28 | 57 57 4 | 28 1 9 |
| 58 7 19 | 16 169 2 | 58 3 4 |
+--------------+----------+---------------+
| Quote: | Correct formulas
X wing 2 ( line 2 and line 8 )-->-2R1C3 -2R3C3 -2R7C7 -2R1C7 -2R5C7
AIC R8C3≠8=>R9C1=8=>R4C1≠8=>R4C1=6=>R4C3≠6=>R3C3=6=>R3C3≠8=>-8 R3C3
AIC R8C3≠8=>R9C1=8=>R4C1≠8=>R4C1=6=>R4C3≠6=>R3C3=6=>R3C3≠3=>R1C3=3=>R1C3≠8=>-8 R1C3 |
Paolo,
What are you trying to tell us with the two AICs? Do they get performed consecutively? The first one says r3c3<>8 and the second one, r1c3<>8. What does it all mean? What is your solution to the puzzle? |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Wed May 31, 2017 8:26 pm Post subject: |
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| Code: |
+--------------+----------+---------------+
| 1 4 238 | 9 27 6 | 237 5 2378 |
| 7 5 29 | 3 4 8 | 29 6 1 |
| 268 89 23689 | 17 127 5 | 4 279 2378 |
+--------------+----------+---------------+
| 68 2 678 | 4 38 1 | 379 79 5 |
| 4 3 17 | 56 56 9 | 127 8 27 |
| 9 18 5 | 2 38 7 | 136 4 36 |
+--------------+----------+---------------+
| 25 19 4 | 8 19 3 | 2567 27 267 |
| 3 6 28 | 57 57 4 | 28 1 9 |
| 58 7 19 | 16 169 2 | 58 3 4 |
+--------------+----------+---------------+
|
Play this puzzle online at the Daily Sudoku site
After x wing and insert single 2
| Code: |
+-------------+----------+------------+
| 1 4 38 | 9 2 6 | 37 5 378 |
| 7 5 29 | 3 4 8 | 29 6 1 |
| 268 89 3689 | 17 17 5 | 4 29 38 |
+-------------+----------+------------+
| 68 2 678 | 4 38 1 | 379 79 5 |
| 4 3 17 | 56 56 9 | 17 8 2 |
| 9 18 5 | 2 38 7 | 136 4 36 |
+-------------+----------+------------+
| 25 19 4 | 8 19 3 | 567 27 67 |
| 3 6 28 | 57 57 4 | 28 1 9 |
| 58 7 19 | 16 169 2 | 58 3 4 |
+-------------+----------+------------+
|
Play this puzzle online at the Daily Sudoku site
It sufficient for solution only second AIC -8 in R1C3.
| Code: |
+-------------+----------+------------+
| 1 4 3 | 9 2 6 | 37 5 378 |
| 7 5 29 | 3 4 8 | 29 6 1 |
| 268 89 3689 | 17 17 5 | 4 29 38 |
+-------------+----------+------------+
| 68 2 678 | 4 38 1 | 379 79 5 |
| 4 3 17 | 56 56 9 | 17 8 2 |
| 9 18 5 | 2 38 7 | 136 4 36 |
+-------------+----------+------------+
| 25 19 4 | 8 19 3 | 567 27 67 |
| 3 6 28 | 57 57 4 | 28 1 9 |
| 58 7 19 | 16 169 2 | 58 3 4 |
+-------------+----------+------------+
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Play this puzzle online at the Daily Sudoku site
Solution
| Code: |
+-------------+----------+--------------+
| 1 4 3 | 9 2 6 | 7 5 8 |
| 7 5 9 | 3 4 8 | 2 6 1 |
| 2 8 6 | 1 7 5 | 4 9 3 |
+-------------+----------+--------------+
| 6 2 8 | 4 3 1 | 9 7 5 |
| 4 3 7 | 5 6 9 | 1 8 2 |
| 9 1 5 | 2 8 7 | 3 4 6 |
+-------------+----------+--------------+
| 5 9 4 | 8 1 3 | 6 2 7 |
| 3 6 2 | 7 5 4 | 8 1 9 |
| 8 7 1 | 6 9 2 | 5 3 4 |
+-------------+----------+--------------+
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Play this puzzle online at the Daily Sudoku site |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Wed May 31, 2017 8:40 pm Post subject: |
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Hi Marty R.
The logic of two AIC is the same.
When 8 in r8c3 is made in turn true and false the 8 in R1C3 and R3C3 is
always false, there is a contradiction, so 8 in R1C3 and R3C3 can be removed.
Ciao a tutti
Paolo |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Wed May 31, 2017 11:25 pm Post subject: |
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| Quote: | | It sufficient for solution only second AIC -8 in R1C3. |
Sorry to be such a pest with all these questions. If after the X-Wing, AIC #2 is sufficient, what is the purpose of #1 and why show it? What is the reader to think?
| Quote: | When 8 in r8c3 is made in turn true and false the 8 in R1C3 and R3C3 is
always false, there is a contradiction, so 8 in R1C3 and R3C3 can be removed. |
I do not understand anything about this sentence. Do you know how to write Eureka notation? That can answer a lot of questions and show exactly what is being done. |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Thu Jun 01, 2017 7:56 am Post subject: |
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Dear Marty
The first puzzle is in my previous post is the initial problem that you put .
The second puzzle represents the situation after the x-wing of the 2 and
other insertions and eliminations with basic strategies, including the 2 in first line (R1C5).
The third puzzle is simply obtained by eliminating the 8 in R1C3 which easily leads to the solution.
The fourth is the solution.
Last edited by Ajò Dimonios on Thu Jun 01, 2017 8:29 am; edited 1 time in total |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Thu Jun 01, 2017 8:27 am Post subject: |
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| Quote: | When 8 in r8c3 is made in turn true and false the 8 in R1C3 and R3C3 is
always false, there is a contradiction, so 8 in R1C3 and R3C3 can be removed. |
It is simply a demonstration of the logical process of the AIC chain leading to the elimination of the 8 in R1C3 and R3C3.
In fact, the 8 in R8C3 "sees" both 8 in R1C3 and R3C3. So when R8C3 = 8 is true the other 8 are false (weak inference).
The second is the strong inference of the AIC chain
| Quote: | AIC R8C3≠8=>R9C1=8=>R4C1≠8=>R4C1=6=>R4C3≠6=>R3C3=6=>R3C3≠8=>-8 R3C3
AIC R8C3≠8=>R9C1=8=>R4C1≠8=>R4C1=6=>R4C3≠6=>R3C3=6=>R3C3≠3=>R1C3=3=>R1C3≠8=>-8 R1C3
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Which shows that when R8C3 is false even 8 in R1C3 and R3C3 are false.Then 8 in R1C3 and R3C3 can be eliminated because either that 8 in R8C3 is true or false the 8 in R1C3 and r3C3 are always false (contradiction).
I hope I have been clear, even though my English is not very correct.
Ciao a Tutti
Paolo |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Thu Jun 01, 2017 11:47 am Post subject: |
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I hope that this is my final post in this thread.
| Quote: | The second is the strong inference of the AIC chain
Quote:
AIC R8C3≠8=>R9C1=8=>R4C1≠8=>R4C1=6=>R4C3≠6=>R3C3=6=>R3C3≠8=>-8 R3C3
AIC R8C3≠8=>R9C1=8=>R4C1≠8=>R4C1=6=>R4C3≠6=>R3C3=6=>R3C3≠3=>R1C3=3=>R1C3≠8=>-8 R1C3
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Is this considered two branches of one chain?
| Quote: | | Which shows that when R8C3 is false even 8 in R1C3 and R3C3 are false.Then 8 in R1C3 and R3C3 can be eliminated because either that 8 in R8C3 is true or false the 8 in R1C3 and r3C3 are always false (contradiction) |
You talk about r8c3 being true or false but I don't see any chain with r8c3=8 being the opening premise.
Yes, r1c3 and r3c3<>8 when r8c3 is either true or false. I don't understand where the contradiction is. it looks to me like a common outcome of a forcing chain.
Is that the solution, that both r1r3c3 and r3c3 are false? Does the elimination of those two 8s finish the puzzle? |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Thu Jun 01, 2017 4:42 pm Post subject: |
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| Quote: |
AIC R8C3≠8=>R9C1=8=>R4C1≠8=>R4C1=6=>R4C3≠6=>R3C3=6=>R3C3≠8=>-8 R3C3
AIC R8C3≠8=>R9C1=8=>R4C1≠8=>R4C1=6=>R4C3≠6=>R3C3=6=>R3C3≠3=>R1C3=3=>R1C3≠8=>-8 R1C3 |
| Quote: | | Is this considered two branches of one chain? |
No, there are two independent AICs that share the initial cell and the first part to cell R3C3 = 6. One eliminates 8 in R1C3 and the other eliminates 8 in R3C3. |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Thu Jun 01, 2017 4:55 pm Post subject: |
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| Quote: | | You talk about r8c3 being true or false but I don't see any chain with r8c3=8 being the opening premise. |
The premise is implicit in the fact that 8 in R3C8 "sees" the cells R1C3 and R3C3. This means that there is a weak inference between them.
In each AIC, the head and tail of the chain must "see" the cells where the elimination occurs. |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Thu Jun 01, 2017 5:08 pm Post subject: |
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| Quote: | | Yes, r1c3 and r3c3<>8 when r8c3 is either true or false. I don't understand where the contradiction is. it looks to me like a common outcome of a forcing chain. |
With contradiction I mean an impossible situation. Cell R1C3 and R3C3 cell can never contain 8 as a value, because it is impossible that in cell R8C3 the 8 is both true and false at the same time (premise of logical reasoning). |
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Ajò Dimonios
Joined: 01 May 2017
Posts: 339
Location: Sassari Italy
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| Posted: Thu Jun 01, 2017 5:22 pm Post subject: |
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| Quote: | | Is that the solution, that both r1r3c3 and r3c3 are false? Does the elimination of those two 8s finish the puzzle? |
As I said in a previous post, to reach the solution is enough to eliminate 8 in R1C3.The second elimination is supposed to be easily accessed by the basic technique
Saluti a tutti
Paolo |
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