Hi,

I have 10 comma delimited number pairs:
1,2
1,3
1,4
1,5
2,3
2,4
2,5
3,4
3,5
4,5

I have 10 letters. Each of the letters can represent 3 of the of the comma delimited pairs. ie:

a 1,2 1,3 2,3
b 1,2 1,4 2,4
c 1,2 1,5 2,5
d 1,3 1,4 3,4
e 1,3 1,5 3,5
f 1,4 1,5 4,5
g 2,3 2,4 3,4
h 2,3 2,5 3,5
i 2,4 2,5 4,5
j 3,4 3,5 4,5

How do I figure out the least number of letters that will represent all of the comma delimited number pairs. ie: I was able to eye ball the list and figure out that j,i,f,a will do it. But how do you program logic. How about representing the numbers in data tables and using joins and unions. Any takers?

Neil