a form of xy-chain ?

Post the puzzle or solving technique that's causing you trouble and someone will help

a form of xy-chain ?

Postby 7b53 » Mon Aug 20, 2012 4:09 am

say from a bivalve cell of x,y (r1c1)
if we start the chain with x , and somehow (r1c9) end up to be digit z
then we can say r1c9<>y
so the logic goes....
when r1c1=x =>r1c9=z => r1c9<>y
when r1c1=Y =>r1c9<>y
just wondering if this related to xy-chain ?
7b53
2012 Supporter
 
Posts: 156
Joined: 01 January 2012
Location: New York

Re: a form of xy-chain ?

Postby champagne » Mon Aug 20, 2012 6:43 am

I would say that to name the chain, you have to tell what set of rules you are using;

You surely describe a contradiction.

In Sudoku Explainer, this can be

an xy chain
a dynamic chain
a dynamic plus chain
a nested chain

depending on the rules you apply

champagne
champagne
2017 Supporter
 
Posts: 5677
Joined: 02 August 2007
Location: France Brittany

Re: a form of xy-chain ?

Postby 7b53 » Fri Aug 24, 2012 1:58 am

not sure your meaning... champagne :
there were no set of rules nor did i apply anything.
maybe i should ask this instead...
is this consider a solving technique ?
7b53
2012 Supporter
 
Posts: 156
Joined: 01 January 2012
Location: New York

Re: a form of xy-chain ?

Postby champagne » Fri Aug 24, 2012 6:20 am

7b53 wrote:not sure your meaning... champagne :
there were no set of rules nor did i apply anything.
maybe i should ask this instead...
is this consider a solving technique ?


Hi 7b53,

It seems you are waiting for a precise answer.

If so, the prerequisite is to provide a precise description of the situation, say a PM and the chain(s) hidden below

when r1c1=x =>r1c9=z => r1c9<>y

I am not expert in techniques names, that's why I referred to names in use in Sudoku Explainer, but this can come out of (among others)

Code: Select all
a chain of bivalues  then Sudoku Explainer calls it an xy chain

several kinds of left driven chain of increasing complexity

just using basic rules and then you get a  dynamic chain in Sudoku Explainer
Adding left created pairs .... and then you have a dynamic plus chain in Sudoku Explainer
adding nested eliminations chains and then you have nested chains of various complexity in Sudolu Explainer



Basically, an xy chain is a subset of Alternate Inference Chains. That family can have many other forms.

I am aware that this is very general, but without the PM and the chain, nothing short can be said

champagne
champagne
2017 Supporter
 
Posts: 5677
Joined: 02 August 2007
Location: France Brittany

Re: a form of xy-chain ?

Postby ronk » Fri Aug 24, 2012 11:52 am

7b53 wrote:say from a bivalve cell of x,y (r1c1)
if we start the chain with x , and somehow (r1c9) end up to be digit z
then we can say r1c9<>y
so the logic goes....
when r1c1=x =>r1c9=z => r1c9<>y
when r1c1=Y =>r1c9<>y
just wondering if this related to xy-chain ?

If a chain is comprised 100% of bivalued cells, it is an xy-chain. If comprised 100% of bilocal strong inferences (links), i.e., with two grouped or ungrouped like-candidates in a row, column or box, then it might be called a bilocal chain. A mix of bivalues and bilocals is a mixed chain, or simply a chain.

I'd recommend forgetting, at least for now, the Sudoku Explainer terminology mentioned by champagne. Dynamic, dynamic+, and nested forcing chains are really "networks" instead of chains, are needed only in puzzles beyond the capability of most human solvers, and are terms not generally used on this forum.
ronk
2012 Supporter
 
Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

Re: a form of xy-chain ?

Postby 7b53 » Sun Aug 26, 2012 8:16 am

actually, its not so much about the terminology.
rather, is the method of the elimination.
thank you anyway, champagne and ronk. and sorry for the confusion.

i notice that some or most solvers doesnot include this type of elimination.
as this might be very simple or childish for most of you.
but to the newbies,including myself, could be quite interesting.

there are exactly 20 cells which (r1c1) can "see" , including (r1c9).
by placing an x into (r1c1), from here... it may or maynot involve any chains.
basically, is whatever you need to do to help you spot a digit z into one of those 20 cells.
as long as you can find one, you will have an elimination.
in this case, it will be digit y .

and what is digit z ? digit z can be any digit as long as.... is not an x or y .
so most likely, this is not an xy-chain.

btw, can anyone tell me when can i use the pm ? do i have to donate 10 bucks or what ?
Last edited by 7b53 on Sun Sep 09, 2012 7:22 pm, edited 1 time in total.
7b53
2012 Supporter
 
Posts: 156
Joined: 01 January 2012
Location: New York

Re: a form of xy-chain ?

Postby champagne » Sun Aug 26, 2012 12:53 pm

7b53 wrote:btw, can anyone tell me when can i use the pm ? do i have to donate 10 bucks or what ?

as far a I know, it's possible to send pm after the third post, so you should be in a position to do it now
champagne
2017 Supporter
 
Posts: 5677
Joined: 02 August 2007
Location: France Brittany


Return to Help with puzzles and solving techniques