[6548] in s-news-athena

home help back first fref pref prev next nref lref last post

COMBO OPTIMISATION BY ELIMINATING SUB SETS

daemon@ATHENA.MIT.EDU (News Reader)
Wed Mar 1 21:53:42 1995

To: s-news@utstat.toronto.edu
From: dwh@bom.gov.au (News Reader)
Date: Thu, 2 Mar 1995 01:16:55 GMT

COMBO OPTIMISATION BY ELIMINATING
DUPLICATE COMBO 4 & 5  SUB-SETS

Consider a simple example  7 number combination of 1,2,3,4,5,6,7
Represented as 6 number combination subsets.
6 from 7 standard combos as follows

combo 1   1, 2, 3, 4, 5, 6
combo 2   1, 2, 3, 4, 5, 7
combo 3   1, 2, 3, 4, 6, 7
combo 4   1, 2, 3, 5, 6, 7
combo 5   1, 2, 4, 5, 6, 7
combo 6   1, 3, 4, 5, 6, 7
combo 7   2, 3, 4, 5, 6, 7

All combinations have at most 5 numbers in common
Thus if I wanted to aviod combinations with 4 or 5 numbers
in common I could eliminate 6 out of the 7 combos.

Is there a general formula that can be applied
ie; to give minimum overlap of numbers for a given combination.

As seen in the 7 number combo set when broken into 6
number combo sub sets, each number appears in all but 1 combo
I'm sure there must be a formula ! You probably already know it ?

RULES
Thus for a combo of  7 numbers broken into 6 number sub sets
and eliminating all sub sets that share 4 or 5 numbers with any
other subset I am left with only 1 sub set.

If I had 8 numbers broken into 6 number sub sets, how many
6 number subsets would I have left is I applied the same rules.
ie; eliminating all combos which shared 4 or 5 numbers with
any other subset ?

If I had 9 numbers broken into 6 number sub sets ?

If I had 10 numbers broken into 6 number sub sets ?

etc........

There must be a general formula one can apply ?

Any help appreciated
Thanks

David 

home help back first fref pref prev next nref lref last post