The New Sudoku Players' Forum

[ronk]

for example :
two cells ab, abc
[...]
A statement can however be made :
either ab will turn out to be a hidden pair, or if that is not the case, then c is true.

When c is false, how is ab hidden?

[aran]

for example :
two cells ab, abc
[...]
A statement can however be made :
either ab will turn out to be a hidden pair, or if that is not the case, then c is true.

When c is false, how is ab hidden?

With that reasoning, one might as well say that a sudoku consists of 81 naked singles...

[daj95376]

Well, since everyone is critique-ing notation, would the following be acceptable as an alternate for ttt's first chain?

Code: Select all

 *-----------------------------------------------------------*
 | 3     8     67    | 167   256   12    | 257   4     9     |
 | 1     25    9     | 678   4     28    | 2578  268   3     |
 | 67    25    4     | 3     258   9     | 2578  128   16    |
 |-------------------+-------------------+-------------------|
 | 4     3     2     | 9     7     6     | 1     5     8     |
 | 78    6     78    | 2     1     5     | 3     9     4     |
 | 9     1     5     | 48    38    348   | 6     7     2     |
 |-------------------+-------------------+-------------------|
 | 68    4     138   | 5     238   7     | 9     128   16    |
 | 2     7     1368  | 1468  9     1348  | 48    168   5     |
 | 5     9     168   | 1468  268   1248  | 248   3     7     |
 *-----------------------------------------------------------*


(8)r3c5 - (8=2)r2c6 - (2){r1c56=r1c7-r9c7=r7c8-r7c5} = (38)r67c5 - (8)r3c5 => [r3c5]<>8

[ronk]

for example :
two cells ab, abc
[...]
A statement can however be made :
either ab will turn out to be a hidden pair, or if that is not the case, then c is true.

When c is false, how is ab hidden?

With that reasoning, one might as well say that a sudoku consists of 81 naked singles...

aran and I seem to have had problems communicating since day one. Would anyone care to translate that

[ronk]

Well, since everyone is critique-ing notation, would the following be acceptable as an alternate for ttt's first chain?
[...]
(8)r3c5 - (8=2)r2c6 - (2){r1c56=r1c7-r9c7=r7c8-r7c5} = (38)r67c5 - (8)r3c5 => [r3c5]<>8

Finally, something I can understand. Although I might complain a little about it being in AIC notation, and others might complain a little about the weak links at the ends ... it's fine by me.

[aran]

for example :
two cells ab, abc
[...]
A statement can however be made :
either ab will turn out to be a hidden pair, or if that is not the case, then c is true.

When c is false, how is ab hidden?

With that reasoning, one might as well say that a sudoku consists of 81 naked singles...

aran and I seem to have had problems communicating since day one. Would anyone care to translate that

Just in case there's a volunteer translator, I'll wait before giving you the less elliptical version.

[Draco]

Draco, I’m sorry by out of this Topic.

ttt

ttt - Not a problem. I like seeing interesting and different solutions (such as yours). I appreciate it when others chime in to help me understand a posted solution that I cannot decipher (as Ron did).

As for the rest -- well everyone is entitled to their opinion and everyone has the right to say/repeat it as often as they like, I suppose.

Cheers...

- drac

[DonM]

for example :
two cells ab, abc
[...]
A statement can however be made :
either ab will turn out to be a hidden pair, or if that is not the case, then c is true.

When c is false, how is ab hidden?

With that reasoning, one might as well say that a sudoku consists of 81 naked singles...

aran and I seem to have had problems communicating since day one. Would anyone care to translate that

Just in case there's a volunteer translator, I'll wait before giving you the less elliptical version.

I'll give a somewhat broader translation. My guess is that your view of the use of a label allows for a broader application of 'hp' and the like. Digressing for a minute (& not necessarily applying to the way you use these labels), I can see where some might prefer to use hp for anything that remotely fits, as long as the reader has no problem figuring out what's going on. After all, the way I see it, labels are different than the formal names given to, say, the actual 'hidden pair' pattern and there is more room for flexibility.

And that is why I don't think there is necessarily an absolute right or wrong here. There has never been a discussion of what labels should be used where. I may prefer to use 'als' for patterns that others use 'hp' for. I might prefer to use 'hp' where some might use 'ahp'. A discussion might bring about some meeting of the minds on the subject, but even then, for something like this, IMO, there is room for continuing differences of preference. However, there is one thing I do have a strong opinion about: If there are going to be any judgments made about what is allegedly appropriate or not, at the very least, opinions from those who actually use the patterns & related labels in question should have equal value as the opinions from those who don't.

[Luke]

I’ve come home to find that a lot has gone on here this weekend! I’d like to give my simple(ton) perspective.

The solution read, “(hp38=2)r67c5-…..” That is clear. I can see what was intended. In fact, it is more than clear. We have the extra clarification that that the presenter considered the (38)’s an “hp.” An inference was established, the chain was kicked off, no problem.

Say, instead, the solution began, “38r67c5=2r7c5.” A bit less information, but exactly the same meaning. It makes sense on a very basic level to think of the (38)s as a “hidden pair” or set. What else could it possibly mean given the notation? The link simply infers that in the end if we haven’t got a hidden pair, then the (2) must be true.

If someone wants to point out in his notation that this is an ALS, well, cool. There’s three candidates in two cells, that’s indisputable and clear. As before, I appreciate the clarification/extra information that the presenter considered the candidates to be an ALS. The notation is clear, and correct.

Isn’t this the purpose of notation, to present an idea in a way that people can understand it? I think the original presenter accomplished that, no problem.

I just hope he comes back to show us the two move solution. In light of the discussion in a concurrent thread, I want to see that net/AAIC!

[ronk]

The solution read, “(hp38=2)r67c5-…..” That is clear. I can see what was intended. In fact, it is more than clear. We have the extra clarification that that the presenter considered the (38)’s an “hp.” An inference was established, the chain was kicked off, no problem.

(Using "np" for "naked pair") Does that mean you think "(np38=2)r67c5-..." would have been less clear?

[ronk]

Hidden pair = naked pair with clutter.
Remove the clutter, reveal the naked pair.
Your argument is : ergo, it was always a naked pair. With which I for one disagree.

Applied above : if the clutter is removed from (r8c8+r7c9) there is revealed a naked pair 19. Revealed, so it was hidden.

Firstly, I never said "it was always a naked pair". I would say it was always an ALS or an "almost naked n-tuple", such as the "almost naked pair" in this case.

Secondly, you are mixing two different issues, one issue being whether it's a "cluttered naked n-tuple" or a "cluttered hidden n-tuple" to start with, and the second issue being whether to call it by its cluttered or uncluttered name.

If the starting point is an ALS (cluttered naked N-tuple), where there are N+1 candidate values in N cells, it becomes uncluttered by removing one value from one or more of the N cells, leaving a naked n-tuple. If the starting point is an AHS (cluttered hidden N-tuple), where there are N candidate values in N+1 cells, it becomes uncluttered by removing one of the cells, leaving a hidden n-tuple.

[aran]

Hidden pair = naked pair with clutter.
Remove the clutter, reveal the naked pair.
Your argument is : ergo, it was always a naked pair. With which I for one disagree.

Applied above : if the clutter is removed from (r8c8+r7c9) there is revealed a naked pair 19. Revealed, so it was hidden.

Firstly, I never said "it was always a naked pair". I would say it was always an ALS or an "almost naked n-tuple", such as the "almost naked pair" in this case.

Secondly, you are mixing two different issues, one issue being whether it's a "cluttered naked n-tuple" or a "cluttered hidden n-tuple" to start with, and the second issue being whether to call it by its cluttered or uncluttered name.

If the starting point is an ALS (cluttered naked N-tuple), where there are N+1 candidate values in N cells, it becomes uncluttered by removing one value from one or more of the N cells. If the starting point is an AHS (cluttered hidden N-tuple), where there are N candidate values in N+1 cells, it becomes uncluttered by removing one of the cells, leaving a hidden n-tuple.

what is common to both is this : removal=>revelation
remove a candidate, reveal a naked pair
remove a cell (that is the occurrences of the "pair" candidates from that cell, to be clear), reveal a hidden pair.
Revelation in both cases.
Revelation=>previously hidden.
In the first case what is revealed is a (previously) hidden naked pair.
In the second what is revealed is a (previously) hidden hidden pair.
Convenient to combine both notions into "hidden" logic.

[ronk]

Revelation=>previously hidden.
In the first case what is revealed is a (previously) hidden naked pair.
In the second what is revealed is a (previously) hidden hidden pair.

Wow, we actually somewhat agree on something. What I don't agree with is subsequently dropping the primary adjective rather than the secondary adjective, and thereby changing "hidden naked pair" into "hidden pair".

[ttt]

Does that mean you think "(np38=2)r67c5-..." would have been less clear?

Code: Select all

*-----------------------------------------------------------*
 | 3     8     67    | 167   256   12    | 257   4     9     |
 | 1     25    9     | 678   4     28    | 2578  268   3     |
 | 67    25    4     | 3     258   9     | 2578  128   16    |
 |-------------------+-------------------+-------------------|
 | 4     3     2     | 9     7     6     | 1     5     8     |
 | 78    6     78    | 2     1     5     | 3     9     4     |
 | 9     1     5     | 48    38    348   | 6     7     2     |
 |-------------------+-------------------+-------------------|
 | 68    4     138   | 5     238   7     | 9     128   16    |
 | 2     7     1368  | 1468  9     1348  | 48    168   5     |
 | 5     9     168   | 1468  268   1248  | 248   3     7     |
 *-----------------------------------------------------------*

Ah… EUREKA ! Thanks ronk.

As practice :
(np38=2)r67c5, (hp67)r12c4=(6)r1c5, (nt258=7)r3c257, (nt257=8)r123c7, (ht136)r789c3=(6)r1c3…

np – naked pair, nt – naked triple, hp – hidden pair, ht – hidden triple

ttt

[DonM]

ttt, for interest sake, Steve often wrote (pair38=2)r67c5, in this situation.