<?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>Ring _ String -- get a ring variable by name</title> <link rel="stylesheet" type="text/css" href="../../../../Macaulay2/Style/doc.css"/> </head> <body> <table class="buttons"> <tr> <td><div><a href="___Ring_sp_us_sp__Z__Z.html">next</a> | <a href="___Ring_sp_us_sp__List.html">previous</a> | <a href="___Ring_sp_us_sp__Z__Z.html">forward</a> | <a href="___Ring_sp_us_sp__List.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>Ring _ String -- get a ring variable by name</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>R_"x"</tt></div> </dd></dl> </div> </li> <li><span>Operator: <a href="__us.html" title="a binary operator, used for subscripting and access to elements">_</a></span></li> <li><div class="single">Inputs:<ul><li><span><tt>R</tt>, <span>a <a href="___Ring.html">ring</a></span></span></li> <li><span><tt>"x"</tt>, <span>a <a href="___String.html">string</a></span></span></li> </ul> </div> </li> <li><div class="single">Outputs:<ul><li><span><span>a <a href="___Ring__Element.html">ring element</a></span>, the variable of <tt>R</tt> whose name is <tt>x</tt></span></li> </ul> </div> </li> </ul> </div> <div class="single"><h2>Description</h2> <div><table class="examples"><tr><td><pre>i1 : R = ZZ[x,y,z];</pre> </td></tr> <tr><td><pre>i2 : use R;</pre> </td></tr> <tr><td><pre>i3 : S = ZZ[x,t];</pre> </td></tr> <tr><td><pre>i4 : x o4 = x o4 : S</pre> </td></tr> </table> The symbol <tt>x</tt> now refers to the variable <tt>x</tt> in the ring <tt>S</tt>. There are several ways of now referring to <tt>x</tt> in the ring <tt>R</tt>.<table class="examples"><tr><td><pre>i5 : R_0 o5 = x o5 : R</pre> </td></tr> <tr><td><pre>i6 : R_"x" o6 = x o6 : R</pre> </td></tr> <tr><td><pre>i7 : use R;</pre> </td></tr> <tr><td><pre>i8 : x o8 = x o8 : R</pre> </td></tr> </table> </div> </div> <div class="single"><h2>See also</h2> <ul><li><span><a href="___Ring_sp_us_sp__Z__Z.html" title="get a ring variable by index">Ring _ ZZ</a> -- get a ring variable by index</span></li> <li><span><a href="___Symbol_sp_us_sp__Ring.html" title="get a ring variable by name">Symbol _ Ring</a> -- get a ring variable by name</span></li> <li><span><a href="_use_lp__Ring_rp.html" title="install ring variables and ring operations">use(Ring)</a> -- install ring variables and ring operations</span></li> </ul> </div> </div> </body> </html>