Decidability of the generated order - MathOverflow most recent 30 from http://mathoverflow.net2013-05-18T22:27:50Zhttp://mathoverflow.net/feeds/question/109005http://www.creativecommons.org/licenses/by-nc/2.5/rdfhttp://mathoverflow.net/questions/109005/decidability-of-the-generated-orderDecidability of the generated orderLilach Leibovich2012-10-06T15:18:07Z2012-10-06T16:48:18Z
<p>is the question whether a polynomial is non-negative on some semi-algebraic set (equivalently, is it in the cone denerated by some polynomials in the field of rational functions) known to be decidable?</p>
http://mathoverflow.net/questions/109005/decidability-of-the-generated-order/109013#109013Answer by Andreas Blass for Decidability of the generated orderAndreas Blass2012-10-06T16:48:18Z2012-10-06T16:48:18Z<p>Assuming you're working over the real numbers (or at least over a real-closed field), the answer is yes. The question lies within the first-order theory of real-closed fields, and that theory is decidable by an old theorem of Tarski. </p>