<?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>ancestor(Type,Type) -- whether one type is an ancestor of another</title> <link rel="stylesheet" type="text/css" href="../../../../Macaulay2/Style/doc.css"/> </head> <body> <table class="buttons"> <tr> <td><div><a href="_installing_spmethods.html">next</a> | <a href="_instance.html">previous</a> | forward | <a href="_instance.html">backward</a> | <a href="_what_spa_spclass_spis.html">up</a> | <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> <div><a href="index.html" title="">Macaulay2Doc</a> > <a href="___The_sp__Macaulay2_splanguage.html" title="">The Macaulay2 language</a> > <a href="_what_spa_spclass_spis.html" title="">what a class is</a> > <a href="_ancestor_lp__Type_cm__Type_rp.html" title="whether one type is an ancestor of another">ancestor(Type,Type)</a></div> <hr/> <div><h1>ancestor(Type,Type) -- whether one type is an ancestor of another</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>ancestor(x,y)</tt></div> </dd></dl> </div> </li> <li><span>Function: <a href="_ancestor_lp__Type_cm__Type_rp.html" title="whether one type is an ancestor of another">ancestor</a></span></li> <li><div class="single">Inputs:<ul><li><span><tt>x</tt>, <span>a <a href="___Type.html">type</a></span></span></li> <li><span><tt>y</tt>, <span>a <a href="___Type.html">type</a></span></span></li> </ul> </div> </li> <li><div class="single">Outputs:<ul><li><span><span>a <a href="___Boolean.html">Boolean value</a></span>, whether <tt>x</tt> is an ancestor of <tt>y</tt></span></li> </ul> </div> </li> </ul> </div> <div class="single"><h2>Description</h2> <div><p>The ancestors of <tt>y</tt> are <tt>y</tt>, <tt>parent y</tt>, <tt>parent parent y</tt>, and so on.</p> <p>If <tt>x</tt> is an ancestor of <tt>y</tt>, then we also say that <tt>y</tt> is a <em>specialization</em> of <tt>x</tt>.</p> <table class="examples"><tr><td><pre>i1 : parent String o1 = Net o1 : Type</pre> </td></tr> <tr><td><pre>i2 : parent parent String o2 = Thing o2 : Type</pre> </td></tr> <tr><td><pre>i3 : parent parent parent String o3 = Thing o3 : Type</pre> </td></tr> </table> </div> </div> <div class="single"><h2>See also</h2> <ul><li><span><a href="_ancestors.html" title="the ancestors of something">ancestors</a> -- the ancestors of something</span></li> </ul> </div> </div> </body> </html>