<?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>face -- Generate a face.</title>
<link rel="stylesheet" type="text/css" href="../../../../Macaulay2/Style/doc.css"/>
</head>
<body>
<table class="buttons">
<tr>
<td><div><a href="___Face_sp_eq_eq_sp__Face.html">next</a> | <a href="___Face.html">previous</a> | <a href="___Face_sp_eq_eq_sp__Face.html">forward</a> | <a href="___Face.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>face -- Generate a face.</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>face(L)</tt><br/><tt>face(S)</tt><br/><tt>face(L,C)</tt><br/><tt>face(L,C,d,j)</tt></div>
</dd></dl>
</div>
</li>
<li><div class="single">Inputs:<ul><li><span><tt>L</tt>, <span>a <a href="../../Macaulay2Doc/html/___List.html">list</a></span></span></li>
<li><span><tt>S</tt>, <span>a <a href="../../Macaulay2Doc/html/___Set.html">set</a></span></span></li>
<li><span><tt>C</tt>, <span>an <a href="___Complex.html">embedded complex</a></span></span></li>
<li><span><tt>d</tt>, <span>an <a href="../../Macaulay2Doc/html/___Z__Z.html">integer</a></span>, bigger or equal to -1</span></li>
<li><span><tt>j</tt>, <span>an <a href="../../Macaulay2Doc/html/___Z__Z.html">integer</a></span>, non-negative</span></li>
</ul>
</div>
</li>
<li><div class="single">Outputs:<ul><li><span><span>a <a href="___Face.html">face</a></span></span></li>
</ul>
</div>
</li>
</ul>
</div>
<div class="single"><h2>Description</h2>
<div><p>Generate a <a href="___Face.html" title="The class of all faces of complexes or co-complexes.">Face</a> F from a list L (or set S) of vertices. If the additional argument C is given it sets F.ofComplex=C to store the complex of which F is a face of.</p>
<p>If d and j are given then F.indices=d,j for storing the face dimension d and its index j in (F.ofComplex)#0.</p>
<div/>
<table class="examples"><tr><td><pre>i1 : R=QQ[x_0..x_4]
o1 = R
o1 : PolynomialRing</pre>
</td></tr>
<tr><td><pre>i2 : I=ideal(x_0*x_1,x_1*x_2,x_2*x_3,x_3*x_4,x_4*x_0)
o2 = ideal (x x , x x , x x , x x , x x )
0 1 1 2 2 3 3 4 0 4
o2 : Ideal of R</pre>
</td></tr>
<tr><td><pre>i3 : C=idealToComplex I
o3 = 1: x x x x x x x x x x
0 2 0 3 1 3 1 4 2 4
o3 : complex of dim 1 embedded in dim 4 (printing facets)
equidimensional, simplicial, F-vector {1, 5, 5, 0, 0, 0}, Euler = -1</pre>
</td></tr>
<tr><td><pre>i4 : F=C.fc_1_0
o4 = x x
0 2
o4 : face with 2 vertices</pre>
</td></tr>
<tr><td><pre>i5 : F==face(vert F,C,1,0)
o5 = true</pre>
</td></tr>
</table>
</div>
</div>
<div class="single"><h2>See also</h2>
<ul><li><span><a href="___Face.html" title="The class of all faces of complexes or co-complexes.">Face</a> -- The class of all faces of complexes or co-complexes.</span></li>
<li><span><a href="___Complex.html" title="The class of all embedded complexes.">Complex</a> -- The class of all embedded complexes.</span></li>
<li><span><a href="___Co__Complex.html" title="The class of all embedded co-complexes.">CoComplex</a> -- The class of all embedded co-complexes.</span></li>
</ul>
</div>
<div class="waystouse"><h2>Ways to use <tt>face</tt> :</h2>
<ul><li>face(List)</li>
<li>face(List,Complex)</li>
<li>face(List,Complex,ZZ,ZZ)</li>
<li>face(Set)</li>
</ul>
</div>
</div>
</body>
</html>
