<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <title>GAP (Gpd) - Chapter 7: Development History</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8" /> <meta name="generator" content="GAPDoc2HTML" /> <link rel="stylesheet" type="text/css" href="manual.css" /> </head> <body> <div class="chlinktop"><span class="chlink1">Goto Chapter: </span><a href="chap0.html">Top</a> <a href="chap1.html">1</a> <a href="chap2.html">2</a> <a href="chap3.html">3</a> <a href="chap4.html">4</a> <a href="chap5.html">5</a> <a href="chap6.html">6</a> <a href="chap7.html">7</a> <a href="chapBib.html">Bib</a> <a href="chapInd.html">Ind</a> </div> <div class="chlinkprevnexttop"> <a href="chap0.html">Top of Book</a> <a href="chap6.html">Previous Chapter</a> <a href="chapBib.html">Next Chapter</a> </div> <p><a id="X810C43BC7F63C4B4" name="X810C43BC7F63C4B4"></a></p> <div class="ChapSects"><a href="chap7.html#X810C43BC7F63C4B4">7 <span class="Heading">Development History</span></a> <div class="ContSect"><span class="nocss"> </span><a href="chap7.html#X8192EA4C7B7CC5CD">7.1 <span class="Heading">Versions of the Package</span></a> </div> <div class="ContSect"><span class="nocss"> </span><a href="chap7.html#X82148FB77CC3CCC0">7.2 <span class="Heading">What needs to be done next?</span></a> </div> </div> <h3>7 <span class="Heading">Development History</span></h3> <p><a id="X8192EA4C7B7CC5CD" name="X8192EA4C7B7CC5CD"></a></p> <h4>7.1 <span class="Heading">Versions of the Package</span></h4> <p>The first version, <strong class="pkg">GraphGpd</strong> 1.001, formed part of Emma Moore's thesis <a href="chapBib.html#biBemma-thesis">[Moo01]</a> in December 2000, but was not made generally available.</p> <p>Version 1.002 of <strong class="pkg">GraphGpd</strong> was prepared to run under <strong class="pkg">GAP</strong> 4.4 in January 2004; was submitted to the <strong class="pkg">GAP</strong> council to be considered as an accepted package; but suggestions from the referee were not followed up.</p> <p>In April 2006 the manual was converted to <strong class="pkg">GAPDoc</strong> format. Variables <code class="code">Star</code>, <code class="code">Costar</code> and <code class="code">CoveringGroup</code> were found to conflict with usage in other packages, and were renamed <code class="code">VertexStar</code>, <code class="code">VertexCostar</code> and <code class="code">CoveringGroupOfGroupoid</code> respectively. Similarly, the <code class="code">Vertices</code> and <code class="code">Arcs</code> of an <code class="code">FpWeightedDigraph</code> were changed from attributes to record components.</p> <p>In the spring of 2006 the package was extensively rewritten and renamed <strong class="pkg">Gpd</strong>. Version 1.01 was submitted as a deposited package in June 2006. Version 1.03, of October 2007, fixed some file protections, and introduced the test file <code class="file">gpd_manual.tst</code>.</p> <p>Version 1.05, of November 2008, was released because the website at Bangor changed.</p> <p><em>A further extensive rewrite is in progress, introducing magmas with objects and their mappings, but many of the functions fail to work at present, and this manual is far from correct.</em></p> <p><a id="X82148FB77CC3CCC0" name="X82148FB77CC3CCC0"></a></p> <h4>7.2 <span class="Heading">What needs to be done next?</span></h4> <p>Computationally, there are three types of connected groupoid:</p> <ul> <li><p>those with identical object groups,</p> </li> <li><p>those with object groups conjugate in some supergroup,</p> </li> <li><p>those with object groups which are simply isomorphic.</p> </li> </ul> <p><strong class="pkg">GraphGpd</strong> attempted to implement the second case, while <strong class="pkg">Gpd</strong> 1.01 and 1.03 considered only the first case, and <strong class="pkg">Gpd</strong> 1.05 extended 1.03 to the second case. Here are some other immediate requirements:</p> <ul> <li><p>Automorphism group of a groupoid.</p> </li> <li><p>normal subgroupoids and quotient groupoids;</p> </li> <li><p>more methods for morphisms of groupoids, particularly when the range is not connected;</p> </li> <li><p><code class="code">ImageElm</code> and <code class="code">ImagesSource</code> for the cases of groupoid morphisms not yet covered;</p> </li> <li><p><code class="code">Enumerator</code> for <code class="code">IsHomsetCosetsRep</code>;</p> </li> <li><p>free groupoid on a graph;</p> </li> <li><p>methods for <code class="code">FreeProductWithAmalgamation</code> and <code class="code">HnnEntension</code> for pc-groups;</p> </li> <li><p>convert <code class="code">GraphOfGroupsRewritingSystem</code> to the category <code class="code">IsRewritingSystem</code>;</p> </li> <li><p>in <strong class="pkg">XMod</strong>, implement crossed modules over groupoids.</p> </li> </ul> <div class="chlinkprevnextbot"> <a href="chap0.html">Top of Book</a> <a href="chap6.html">Previous Chapter</a> <a href="chapBib.html">Next Chapter</a> </div> <div class="chlinkbot"><span class="chlink1">Goto Chapter: </span><a href="chap0.html">Top</a> <a href="chap1.html">1</a> <a href="chap2.html">2</a> <a href="chap3.html">3</a> <a href="chap4.html">4</a> <a href="chap5.html">5</a> <a href="chap6.html">6</a> <a href="chap7.html">7</a> <a href="chapBib.html">Bib</a> <a href="chapInd.html">Ind</a> </div> <hr /> <p class="foot">generated by <a href="http://www.math.rwth-aachen.de/~Frank.Luebeck/GAPDoc">GAPDoc2HTML</a></p> </body> </html>