{"action":"created","issue":{"url":"https://api.github.com/repos/sympy/sympy/issues/10501","repository_url":"https://api.github.com/repos/sympy/sympy","labels_url":"https://api.github.com/repos/sympy/sympy/issues/10501/labels{/name}","comments_url":"https://api.github.com/repos/sympy/sympy/issues/10501/comments","events_url":"https://api.github.com/repos/sympy/sympy/issues/10501/events","html_url":"https://github.com/sympy/sympy/pull/10501","id":130060455,"number":10501,"title":"10401b: simplification of Relationals","user":{"login":"smichr","id":90703,"avatar_url":"https://avatars.githubusercontent.com/u/90703?v=3","gravatar_id":"","url":"https://api.github.com/users/smichr","html_url":"https://github.com/smichr","followers_url":"https://api.github.com/users/smichr/followers","following_url":"https://api.github.com/users/smichr/following{/other_user}","gists_url":"https://api.github.com/users/smichr/gists{/gist_id}","starred_url":"https://api.github.com/users/smichr/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/smichr/subscriptions","organizations_url":"https://api.github.com/users/smichr/orgs","repos_url":"https://api.github.com/users/smichr/repos","events_url":"https://api.github.com/users/smichr/events{/privacy}","received_events_url":"https://api.github.com/users/smichr/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":16,"created_at":"2016-01-31T01:10:46Z","updated_at":"2016-02-15T21:52:39Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/sympy/sympy/pulls/10501","html_url":"https://github.com/sympy/sympy/pull/10501","diff_url":"https://github.com/sympy/sympy/pull/10501.diff","patch_url":"https://github.com/sympy/sympy/pull/10501.patch"},"body":"ugh. The code is not simple. This is much worse than regular simplification if you try to keep a potentially invalid relationship from becoming valid, e.g. `Lt(x, x + 1)` is invalid if `x == I` so we cannot say that this relationship is automatically true. \r\n\r\nSome key features to keep are\r\n\r\n1. to not reorganize the left and rhs (else an Eq that had something isolated on the lhs may no longer be that way after simplification, e.g. Eq(y, f(x)) could become Eq(y - f(x), 0))\r\n1. to not return an expression whose character will differ from the original (e.g. not have the same singularities, etc...).\r\n\r\ncloses #10401 \r\ncloses #10404 \r\n\r\n- [x] track down why the unrad solution changed\r\n\r\n**References**\r\n____\r\n1. https://groups.google.com/forum/#!searchin/sympy/singularities$20limit/sympy/oaoAIp4DOxQ/cGZoWbf-ieUJ\r\n1. https://github.com/sympy/sympy/wiki/Infinities-and-Singularities\r\n1. https://github.com/sympy/sympy/issues/6091\r\n1. https://github.com/sympy/sympy/pull/971"},"comment":{"url":"https://api.github.com/repos/sympy/sympy/issues/comments/184410183","html_url":"https://github.com/sympy/sympy/pull/10501#issuecomment-184410183","issue_url":"https://api.github.com/repos/sympy/sympy/issues/10501","id":184410183,"user":{"login":"smichr","id":90703,"avatar_url":"https://avatars.githubusercontent.com/u/90703?v=3","gravatar_id":"","url":"https://api.github.com/users/smichr","html_url":"https://github.com/smichr","followers_url":"https://api.github.com/users/smichr/followers","following_url":"https://api.github.com/users/smichr/following{/other_user}","gists_url":"https://api.github.com/users/smichr/gists{/gist_id}","starred_url":"https://api.github.com/users/smichr/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/smichr/subscriptions","organizations_url":"https://api.github.com/users/smichr/orgs","repos_url":"https://api.github.com/users/smichr/repos","events_url":"https://api.github.com/users/smichr/events{/privacy}","received_events_url":"https://api.github.com/users/smichr/received_events","type":"User","site_admin":false},"created_at":"2016-02-15T21:52:39Z","updated_at":"2016-02-15T21:52:39Z","body":"OK, allowing removable singularities to disappear will simplify things, I think. In addition, I think I have a way to handle the case where a ratio of functions (like factorial and gamma) need to simplify. I'll try it some time this week."}}