{"id":332,"date":"2008-05-25T08:33:40","date_gmt":"2008-05-25T14:33:40","guid":{"rendered":"http:\/\/hunch.net\/?p=332"},"modified":"2008-05-25T08:33:40","modified_gmt":"2008-05-25T14:33:40","slug":"inappropriate-mathematics-for-machine-learning","status":"publish","type":"post","link":"https:\/\/hunch.net\/?p=332","title":{"rendered":"Inappropriate Mathematics for Machine Learning"},"content":{"rendered":"<p>Reviewers and students are sometimes greatly concerned by the distinction between:<\/p>\n<ol>\n<li> An <a href=\"http:\/\/en.wikipedia.org\/wiki\/Open_set\">open set<\/a> and a <a href=\"http:\/\/en.wikipedia.org\/wiki\/Closed_set\">closed set<\/a>.<\/li>\n<li>A <a href=\"http:\/\/en.wikipedia.org\/wiki\/Supremum\">Supremum<\/a> and a <a href=\"http:\/\/en.wikipedia.org\/wiki\/Maximal_element\">Maximum<\/a>.<\/li>\n<li>An event which happens with probability 1 and an event that always happens.<\/li>\n<\/ol>\n<p>I don&#8217;t appreciate this distinction in machine learning &#038; learning theory.  All machine learning takes place (by definition) on a machine where every parameter has finite precision.  Consequently, every set is closed, a maximal element always exists, and probability 1 events always happen.<\/p>\n<p>The fundamental issue here is that substantial parts of mathematics don&#8217;t appear well-matched to computation in the physical world, because the mathematics has concerns which are unphysical.  This mismatched mathematics makes irrelevant distinctions.  We can ask &#8220;what mathematics is appropriate to computation?&#8221;  <a href=\"http:\/\/math.andrej.com\/\">Andrej<\/a> has convinced me that a pretty good answer to this question is <a href=\"http:\/\/en.wikipedia.org\/wiki\/Constructive_mathematics\">constructive mathematics<\/a>.<\/p>\n<p>So, here&#8217;s a basic challenge: Can anyone name a situation where any of the distinctions above (or similar distinctions) matter in machine learning?<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Reviewers and students are sometimes greatly concerned by the distinction between: An open set and a closed set. A Supremum and a Maximum. An event which happens with probability 1 and an event that always happens. I don&#8217;t appreciate this distinction in machine learning &#038; learning theory. All machine learning takes place (by definition) on &hellip; <\/p>\n<p class=\"link-more\"><a href=\"https:\/\/hunch.net\/?p=332\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Inappropriate Mathematics for Machine Learning&#8221;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[29,48],"tags":[],"class_list":["post-332","post","type-post","status-publish","format-standard","hentry","category-machine-learning","category-theory"],"_links":{"self":[{"href":"https:\/\/hunch.net\/index.php?rest_route=\/wp\/v2\/posts\/332","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hunch.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hunch.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hunch.net\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/hunch.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=332"}],"version-history":[{"count":0,"href":"https:\/\/hunch.net\/index.php?rest_route=\/wp\/v2\/posts\/332\/revisions"}],"wp:attachment":[{"href":"https:\/\/hunch.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=332"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hunch.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=332"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hunch.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=332"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}