<?xml version="1.0" encoding="utf-8" ?> <!-- for emacs: -*- coding: utf-8 -*- --> <!-- Apache may like this line in the file .htaccess: AddCharset utf-8 .html --> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0 plus SVG 1.1//EN" "http://www.w3.org/2002/04/xhtml-math-svg/xhtml-math-svg-flat.dtd" > <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head><title>isConstant -- whether a ring element is constant</title> <link rel="stylesheet" type="text/css" href="../../../../Macaulay2/Style/doc.css"/> </head> <body> <table class="buttons"> <tr> <td><div><a href="_is__Direct__Sum.html">next</a> | <a href="_is__Commutative.html">previous</a> | <a href="_is__Direct__Sum.html">forward</a> | <a href="_is__Commutative.html">backward</a> | up | <a href="index.html">top</a> | <a href="master.html">index</a> | <a href="toc.html">toc</a> | <a href="http://www.math.uiuc.edu/Macaulay2/">Macaulay2 web site</a></div> </td> </tr> </table> <hr/> <div><h1>isConstant -- whether a ring element is constant</h1> <div class="single"><h2>Synopsis</h2> <ul><li><div class="list"><dl class="element"><dt class="heading">Usage: </dt><dd class="value"><div><tt>isConstant f</tt></div> </dd></dl> </div> </li> <li><div class="single">Inputs:<ul><li><span><tt>f</tt></span></li> </ul> </div> </li> <li><div class="single">Outputs:<ul><li><span><span>a <a href="___Boolean.html">Boolean value</a></span>, whether f is constant, i.e., is in the coefficient ring</span></li> </ul> </div> </li> </ul> </div> <div class="single"><h2>Description</h2> <div><table class="examples"><tr><td><pre>i1 : isConstant 3 o1 = true</pre> </td></tr> <tr><td><pre>i2 : QQ[a,b][x,y];</pre> </td></tr> <tr><td><pre>i3 : isConstant (x+a-x) o3 = true</pre> </td></tr> <tr><td><pre>i4 : isConstant x o4 = false</pre> </td></tr> </table> </div> </div> <div class="single"><h2>See also</h2> <ul><li><span><a href="_coefficient__Ring.html" title="get the coefficient ring">coefficientRing</a> -- get the coefficient ring</span></li> </ul> </div> <div class="waystouse"><h2>Ways to use <tt>isConstant</tt> :</h2> <ul><li>isConstant(RingElement)</li> </ul> </div> <div class="waystouse"><div class="single"><h2>Code</h2> <pre>../../m2/enginering.m2:595:29-595:65: --source code: isConstant RingElement := r -> liftable(r, coefficientRing ring r)</pre> </div> </div> </div> </body> </html>