most recent 30 from http://mathoverflow.net 2013-05-23T21:47:21Z http://mathoverflow.net/feeds/question/94402 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/94402/changing-the-type-of-a-module-in-magma dward1996 2012-04-18T13:45:37Z 2012-04-18T14:19:32Z

<p>I am currently working with irreducible $k[G]$-modules in MAGMA for finite fields $k$ and finite groups $G$. To construct these modules, I am using the commands <strong>IrreducibleModules(G,k)</strong> This results in MAGMA recognising the modules as being of type $ModGrp$. However, I wish to perform calculations such as finding the projective cover of such a module, for which MAGMA can only perform such calculations on modules over algebras (i.e. of type $ModAlg$). Is there an easy way to coerce MAGMA into treating modules of type $ModGrp$ as being of type $ModAlg$?</p>

http://mathoverflow.net/questions/94402/changing-the-type-of-a-module-in-magma/94406#94406 Alastair Litterick 2012-04-18T14:19:32Z 2012-04-18T14:19:32Z

<p>MAGMA is perfectly capable of calculating the projective cover of a member of <code>IrreducibleModules(G,k)</code>, via the <code>ProjectiveCover()</code> function. You can also just call <code>ProjectiveIndecomposables(G,k)</code>. Perhaps you are running an old version of MAGMA? Version 2.18-3 is certainly capable of this functionality.</p> <p>(This would have been a comment rather than an answer if reputation allowed).</p>