most recent 30 from http://mathoverflow.net 2013-05-22T02:36:07Z http://mathoverflow.net/feeds/question/43012 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/43012/another-name-for-a-discrete-set op1 2010-10-21T05:33:09Z 2010-10-21T08:00:21Z

<p>By discrete set, I mean sorting a given number of items into different orders, so that no two sets are alike.</p> <pre><code>Example, 4 items: 1234 3142 2413 4321 </code></pre> <p>It seems related to a "derangement", but is more specific. So maybe there's a specific term for this, besides "discrete set", which is all I could think of.</p> <p>EDIT:</p> <p>Now that I'm looking at latin squares, the following example of a latin square actually repeats sequences between columns (such as 34, 21, 43), whereas my example above does not.</p> <pre><code>1234 2143 3412 4321 </code></pre> <p>Is my non repeating example a particular kind of latin square or is that not distinguished from other latin squares which repeat sequences?</p>