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<div class="ChapSects" ><a href="chap6_mj.html#X7BD5B55C802805B4" >6 <span class="Heading" >Generators</span ></a>
<div class="ContSect" ><span class="tocline" ><span class="nocss" > </span ><a href="chap6_mj.html#X827B67D27E3B91FC" >6.1 <span class="Heading" >Generators: Categories and Representations</span ></a>
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<span class="ContSS" ><br /><span class="nocss" > </span ><a href="chap6_mj.html#X79A6BA1280510584" >6.1-1 IsHomalgGenerators</a></span >
<span class="ContSS" ><br /><span class="nocss" > </span ><a href="chap6_mj.html#X83E88425797FFC9C" >6.1-2 IsHomalgGeneratorsOfLeftModule</a></span >
<span class="ContSS" ><br /><span class="nocss" > </span ><a href="chap6_mj.html#X86E9029487FE58DF" >6.1-3 IsHomalgGeneratorsOfRightModule</a></span >
<span class="ContSS" ><br /><span class="nocss" > </span ><a href="chap6_mj.html#X8671AA997D666F04" >6.1-4 IsGeneratorsOfModuleRep</a></span >
<span class="ContSS" ><br /><span class="nocss" > </span ><a href="chap6_mj.html#X78512B8A8613FBF1" >6.1-5 IsGeneratorsOfFinitelyGeneratedModuleRep</a></span >
</div ></div >
<div class="ContSect" ><span class="tocline" ><span class="nocss" > </span ><a href="chap6_mj.html#X8289206C81622597" >6.2 <span class="Heading" >Generators: Constructors</span ></a>
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<div class="ContSect" ><span class="tocline" ><span class="nocss" > </span ><a href="chap6_mj.html#X8576E1368448066B" >6.3 <span class="Heading" >Generators: Properties</span ></a>
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<span class="ContSS" ><br /><span class="nocss" > </span ><a href="chap6_mj.html#X7ED359D87D6B2F79" >6.3-1 IsReduced</a></span >
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<div class="ContSect" ><span class="tocline" ><span class="nocss" > </span ><a href="chap6_mj.html#X7E136BCD7F22B571" >6.4 <span class="Heading" >Generators: Attributes</span ></a>
</span >
<div class="ContSSBlock" >
<span class="ContSS" ><br /><span class="nocss" > </span ><a href="chap6_mj.html#X7B6F787085536F90" >6.4-1 ProcedureToReadjustGenerators</a></span >
</div ></div >
<div class="ContSect" ><span class="tocline" ><span class="nocss" > </span ><a href="chap6_mj.html#X7AC876EC8137AEA4" >6.5 <span class="Heading" >Generators: Operations and Functions</span ></a>
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<h3>6 <span class="Heading" >Generators</span ></h3>
<p>To present a left/right module it suffices to take a matrix <var class="Arg" >rel</var > and interpret its rows/columns as relations among <span class="SimpleMath" >\(n\)</span > <em >abstract</em > generators, where <span class="SimpleMath" >\(n\)</span > is the number of columns/rows of <var class="Arg" >rel</var >. Only that these abstract generators are useless when it comes to specific modules like modules of homomorphisms, where one expects the generators to be maps between modules. For this reason a presentation of a module in <strong class="pkg" >homalg</strong > is not merely a matrix of relations, but together with a set of generators.</p>
<p>In <strong class="pkg" >homalg</strong > a set of generators of a left/right module is given by a matrix <var class="Arg" >gen</var > with rows/columns being interpreted as the generators.</p>
<p>The data structure of a module in <strong class="pkg" >homalg</strong > is designed to contain not only one but several sets of generators (together with their sets of relations (--> Chapter <a href="chap5_mj.html#X838651287FCCEFD8" ><span class="RefLink" >5</span ></a>)). The different sets of generators are linked with so-called transition matrices (--> Chapter <a href="chap7_mj.html#X8183A6857B0C3633" ><span class="RefLink" >7</span ></a>).</p>
<p><a id="X827B67D27E3B91FC" name="X827B67D27E3B91FC" ></a></p>
<h4>6.1 <span class="Heading" >Generators: Categories and Representations</span ></h4>
<p><a id="X79A6BA1280510584" name="X79A6BA1280510584" ></a></p>
<h5>6.1-1 IsHomalgGenerators</h5>
<div class="func" ><table class="func" width="100%" ><tr ><td class="tdleft" ><code class="func" >‣ IsHomalgGenerators</code >( <var class="Arg" >rel</var > )</td ><td class="tdright" >( category )</td ></tr ></table ></div >
<p>Returns: <code class="code" >true</code > or <code class="code" >false</code ></p>
<p>The <strong class="pkg" >GAP</strong > category of <strong class="pkg" >homalg</strong > generators.</p>
<p><a id="X83E88425797FFC9C" name="X83E88425797FFC9C" ></a></p>
<h5>6.1-2 IsHomalgGeneratorsOfLeftModule</h5>
<div class="func" ><table class="func" width="100%" ><tr ><td class="tdleft" ><code class="func" >‣ IsHomalgGeneratorsOfLeftModule</code >( <var class="Arg" >rel</var > )</td ><td class="tdright" >( category )</td ></tr ></table ></div >
<p>Returns: <code class="code" >true</code > or <code class="code" >false</code ></p>
<p>The <strong class="pkg" >GAP</strong > category of <strong class="pkg" >homalg</strong > generators of a left module.</p>
<p>(It is a subcategory of the <strong class="pkg" >GAP</strong > category <code class="code" >IsHomalgGenerators</code >.)</p>
<p><a id="X86E9029487FE58DF" name="X86E9029487FE58DF" ></a></p>
<h5>6.1-3 IsHomalgGeneratorsOfRightModule</h5>
<div class="func" ><table class="func" width="100%" ><tr ><td class="tdleft" ><code class="func" >‣ IsHomalgGeneratorsOfRightModule</code >( <var class="Arg" >rel</var > )</td ><td class="tdright" >( category )</td ></tr ></table ></div >
<p>Returns: <code class="code" >true</code > or <code class="code" >false</code ></p>
<p>The <strong class="pkg" >GAP</strong > category of <strong class="pkg" >homalg</strong > generators of a right module.</p>
<p>(It is a subcategory of the <strong class="pkg" >GAP</strong > category <code class="code" >IsHomalgGenerators</code >.)</p>
<p><a id="X8671AA997D666F04" name="X8671AA997D666F04" ></a></p>
<h5>6.1-4 IsGeneratorsOfModuleRep</h5>
<div class="func" ><table class="func" width="100%" ><tr ><td class="tdleft" ><code class="func" >‣ IsGeneratorsOfModuleRep</code >( <var class="Arg" >rel</var > )</td ><td class="tdright" >( representation )</td ></tr ></table ></div >
<p>Returns: <code class="code" >true</code > or <code class="code" >false</code ></p>
<p>The <strong class="pkg" >GAP</strong > representation of a finite set of generators of a <strong class="pkg" >homalg</strong > module.</p>
<p>(It is a representation of the <strong class="pkg" >GAP</strong > category <code class="func" >IsHomalgGenerators</code > (<a href="chap6_mj.html#X79A6BA1280510584" ><span class="RefLink" >6.1-1</span ></a>))</p>
<div class="example" ><pre >
DeclareRepresentation( "IsGeneratorsOfModuleRep" ,
IsHomalgGenerators,
[ "generators" ] );
</pre ></div >
<p><a id="X78512B8A8613FBF1" name="X78512B8A8613FBF1" ></a></p>
<h5>6.1-5 IsGeneratorsOfFinitelyGeneratedModuleRep</h5>
<div class="func" ><table class="func" width="100%" ><tr ><td class="tdleft" ><code class="func" >‣ IsGeneratorsOfFinitelyGeneratedModuleRep</code >( <var class="Arg" >rel</var > )</td ><td class="tdright" >( representation )</td ></tr ></table ></div >
<p>Returns: <code class="code" >true</code > or <code class="code" >false</code ></p>
<p>The <strong class="pkg" >GAP</strong > representation of a finite set of generators of a finitely generated <strong class="pkg" >homalg</strong > module.</p>
<p>(It is a representation of the <strong class="pkg" >GAP</strong > representation <code class="func" >IsGeneratorsOfModuleRep</code > (<a href="chap6_mj.html#X8671AA997D666F04" ><span class="RefLink" >6.1-4</span ></a>))</p>
<div class="example" ><pre >
DeclareRepresentation( "IsGeneratorsOfFinitelyGeneratedModuleRep" ,
IsGeneratorsOfModuleRep,
[ "generators" , "relations_of_hullmodule" ] );
</pre ></div >
<p><a id="X8289206C81622597" name="X8289206C81622597" ></a></p>
<h4>6.2 <span class="Heading" >Generators: Constructors</span ></h4>
<p><a id="X8576E1368448066B" name="X8576E1368448066B" ></a></p>
<h4>6.3 <span class="Heading" >Generators: Properties</span ></h4>
<p><a id="X7ED359D87D6B2F79" name="X7ED359D87D6B2F79" ></a></p>
<h5>6.3-1 IsReduced</h5>
<div class="func" ><table class="func" width="100%" ><tr ><td class="tdleft" ><code class="func" >‣ IsReduced</code >( <var class="Arg" >gen</var > )</td ><td class="tdright" >( property )</td ></tr ></table ></div >
<p>Returns: <code class="code" >true</code > or <code class="code" >false</code ></p>
<p>Check if the <strong class="pkg" >homalg</strong > set of generators <var class="Arg" >gen</var > is marked reduced. <br /> (no method installed)</p>
<p><a id="X7E136BCD7F22B571" name="X7E136BCD7F22B571" ></a></p>
<h4>6.4 <span class="Heading" >Generators: Attributes</span ></h4>
<p><a id="X7B6F787085536F90" name="X7B6F787085536F90" ></a></p>
<h5>6.4-1 ProcedureToReadjustGenerators</h5>
<div class="func" ><table class="func" width="100%" ><tr ><td class="tdleft" ><code class="func" >‣ ProcedureToReadjustGenerators</code >( <var class="Arg" >gen</var > )</td ><td class="tdright" >( attribute )</td ></tr ></table ></div >
<p>Returns: a function</p>
<p>A function that takes the rows/columns of <var class="Arg" >gen</var > and returns an object (e.g. a matrix) that can be interpreted as a generator (this is important for modules of homomorphisms).</p>
<p><a id="X7AC876EC8137AEA4" name="X7AC876EC8137AEA4" ></a></p>
<h4>6.5 <span class="Heading" >Generators: Operations and Functions</span ></h4>
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