Minimum unique elements.

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I am looking for algorithm by which I can have smaller fixed number of
element which gives a unique identity for that set.

example: I have
A = { 2,4,6,8}
B = { 3,6,9,12}
C = { 4,8,12,16}

and I like to take minumum 2 element
I can have
A* = { 2,4}
B* = {3,9}
C* = {12,16}
You see that for A* I have to select one of 4,6 or 8, besides 2.
 
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"googleartist" <googleartist@yahoo.com> wrote in message
news:1102351927.793307.239300@z14g2000cwz.googlegroups.com...
> I am looking for algorithm by which I can have smaller fixed number of
> element which gives a unique identity for that set.
>
> example: I have
> A = { 2,4,6,8}
> B = { 3,6,9,12}
> C = { 4,8,12,16}
>
> and I like to take minumum 2 element
> I can have
> A* = { 2,4}
> B* = {3,9}
> C* = {12,16}
> You see that for A* I have to select one of 4,6 or 8, besides 2.

The examples {A, B, C}are displayed in ascending order; is this a matter of
convienience for the newsgroup, or are the sets stored in this manner?

If items are inserted into {A|B|C} in ascending order, then start at 'left'
side, and compare values until there are no matches.
 
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"AngleWyrm" <no_spam_anglewyrm@hotmail.com> wrote in message
news:jqEtd.462970$wV.326875@attbi_s54...
> "googleartist" <googleartist@yahoo.com> wrote in message
> news:1102351927.793307.239300@z14g2000cwz.googlegroups.com...
> > I am looking for algorithm by which I can have smaller fixed number of
> > element which gives a unique identity for that set.
> >
> > example: I have
> > A = { 2,4,6,8}
> > B = { 3,6,9,12}
> > C = { 4,8,12,16}
> >
> > and I like to take minumum 2 element
> > I can have
> > A* = { 2,4}
> > B* = {3,9}
> > C* = {12,16}
> > You see that for A* I have to select one of 4,6 or 8, besides 2.
>
On further examination of the problem, I'm not sure I understand it. The example
A* contains the number {4}, which is not unique to the set A; it is part of the
intersection of A-intersect-C. The set C* also contains a number {12} that is
within the intersection of B-intersect-C.

Could you clarify?
 
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Archived from groups: comp.ai.games (More info?)

Thanks,

Yes,
4 is not unique to A, but {2,4} represents a 2-item ID for "A'" which
sets it apart from 'C' which has id: {12,16}. Since the requirement is
'2', you have to provide atleast 2items if possible for providing
unique ID.
 
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"googleartist" <googleartist@yahoo.com> wrote in message
news:1102710218.179922.301340@c13g2000cwb.googlegroups.com...
<in previous posts>
> I am looking for algorithm by which I can have smaller fixed number of
> element which gives a unique identity for that set.
> example: I have
> A = { 2,4,6,8}
> B = { 3,6,9,12}
> C = { 4,8,12,16}

> and I like to take minumum 2 element
> I can have
> A* = { 2,4}
> B* = {3,9}
> C* = {12,16}
<end previous posts>

> 4 is not unique to A, but {2,4} represents a 2-item ID for "A'" which
> sets it apart from 'C' which has id: {12,16}. Since the requirement is
> '2', you have to provide atleast 2items if possible for providing
> unique ID.

Looks like a database problem, identifying unique key. I have one more question
about this situation. If I make a set of three answers like so:
A' = {2}
B' = {3}
C' = {16}
They seem to characterize their sets uniquely, and identify a width of one
rather than two. In your example, you drew C* from different "columns",
suggesting that the items are not sorted, or arranged in record fields.

Q: Are that the answers {A*, B*, C*} of width two more fitting than the answers
{A', B', C'} of width one, and if so then why/how?

-:|:-
AngleWyrm
 
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AngleWyrm wrote:
> "googleartist" <googleartist@yahoo.com> wrote in message
> news:1102710218.179922.301340@c13g2000cwb.googlegroups.com...
> <in previous posts>
>
>>I am looking for algorithm by which I can have smaller fixed number of
>>element which gives a unique identity for that set.
>>example: I have
>>A = { 2,4,6,8}
>>B = { 3,6,9,12}
>>C = { 4,8,12,16}
>
>
>>and I like to take minumum 2 element
>>I can have
>>A* = { 2,4}
>>B* = {3,9}
>>C* = {12,16}
>
> <end previous posts>
>
>>4 is not unique to A, but {2,4} represents a 2-item ID for "A'" which
>>sets it apart from 'C' which has id: {12,16}. Since the requirement is
>>'2', you have to provide atleast 2items if possible for providing
>>unique ID.
>
>
> Looks like a database problem, identifying unique key. I have one more question
> about this situation. If I make a set of three answers like so:
> A' = {2}
> B' = {3}
> C' = {16}
> They seem to characterize their sets uniquely, and identify a width of one
> rather than two. In your example, you drew C* from different "columns",
> suggesting that the items are not sorted, or arranged in record fields.
>
> Q: Are that the answers {A*, B*, C*} of width two more fitting than the answers
> {A', B', C'} of width one, and if so then why/how?
>
> -:|:-
> AngleWyrm
>
>
judging from the replys have a look for 3-Hitting Set. I know there are
paramterised complexity algorithms for it that have been developed by
fellows and co. www.cs.newcastle.edu.au/~fellows/ should give you a start.