<?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>pyramid -- computes the pyramid over a polyhedron</title> <link rel="stylesheet" type="text/css" href="../../../../Macaulay2/Style/doc.css"/> </head> <body> <table class="buttons"> <tr> <td><div><a href="___Q__Q_sp_st_sp__Polyhedron.html">next</a> | <a href="_proximum.html">previous</a> | <a href="___Q__Q_sp_st_sp__Polyhedron.html">forward</a> | <a href="_proximum.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>pyramid -- computes the pyramid over a polyhedron</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> Q = pyramid P</tt></div> </dd></dl> </div> </li> <li><div class="single">Inputs:<ul><li><span><tt>P</tt>, <span>a <a href="___Polyhedron.html">convex polyhedron</a></span></span></li> </ul> </div> </li> <li><div class="single">Outputs:<ul><li><span><tt>Q</tt>, <span>a <a href="___Polyhedron.html">convex polyhedron</a></span></span></li> </ul> </div> </li> </ul> </div> <div class="single"><h2>Description</h2> <div><p/> <tt>pyramid</tt> takes the polyhedron <tt>P</tt> with ambient dimension n and embeds it into <a href="../../Macaulay2Doc/html/___Q__Q.html" title="the class of all rational numbers">QQ</a>^(n+1) on height 0 with respect to the new last variable. Then it computes the convex hull of the embedded <tt>P</tt> and the point (0,...,0,1).<table class="examples"><tr><td><pre>i1 : P = hypercube 2 o1 = {ambient dimension => 2 } dimension of lineality space => 0 dimension of polyhedron => 2 number of facets => 4 number of rays => 0 number of vertices => 4 o1 : Polyhedron</pre> </td></tr> <tr><td><pre>i2 : Q = pyramid P o2 = {ambient dimension => 3 } dimension of lineality space => 0 dimension of polyhedron => 3 number of facets => 5 number of rays => 0 number of vertices => 5 o2 : Polyhedron</pre> </td></tr> <tr><td><pre>i3 : vertices Q o3 = | -1 1 -1 1 0 | | -1 -1 1 1 0 | | 0 0 0 0 1 | 3 5 o3 : Matrix QQ <--- QQ</pre> </td></tr> </table> </div> </div> <div class="waystouse"><h2>Ways to use <tt>pyramid</tt> :</h2> <ul><li>pyramid(Polyhedron)</li> </ul> </div> </div> </body> </html>