{ "id": "1701.08325", "version": "v1", "published": "2017-01-28T22:08:15.000Z", "updated": "2017-01-28T22:08:15.000Z", "title": "A new relationship between block designs", "authors": [ "Alexander Shramchenko", "Vasilisa Shramchenko" ], "comment": "9 pages", "categories": [ "math.CO" ], "abstract": "We propose a procedure of constructing new block designs starting from a given one by looking at the intersections of its blocks with various sets and grouping those sets according to the structure of the intersections. We introduce a symmetric relationship of friendship between block designs built on a set $V$ and consider families of block designs where all designs are friends of each other, the so-called friendly families. We show that a friendly family admits a partial ordering. Furthermore, we exhibit a map from the power set of $V$, partially ordered by inclusion, to a friendly family of a particular type which preserves the partial order.", "revisions": [ { "version": "v1", "updated": "2017-01-28T22:08:15.000Z" } ], "analyses": { "keywords": [ "partial order", "block designs built", "symmetric relationship", "power set", "intersections" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable" } } }