most recent 30 from http://mathoverflow.net 2013-06-19T10:54:35Z http://mathoverflow.net/feeds/user/21110 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/87442/minimum-number-of-subsets Alya Asarina 2012-02-03T15:41:03Z 2012-04-20T07:11:23Z

<p>This question came up in a practical situation at work...</p> <p>Given a set S of size n, what is the minimum number of subsets of S of size k s.t. each pair of elements of S occurs in the same subset at least once?</p>

http://mathoverflow.net/questions/87442/minimum-number-of-subsets Alya Asarina 2012-04-23T14:47:41Z 2012-04-23T14:47:41Z

Crowdsourcing. :) We wanted to have people rank ~10 or 20 items from best to worst, but thought this would be too much to handle. So the idea was to break the task up into ranking ~5 items at a time, while making sure each pair of items is compared at least once.