[GAP Forum] A Possible bug in FGA

[Laurent Bartholdi]

Hello world,
Unless I'm terribly mistaken there's a problem with the FGA package:

GAP4, Version: 4.4.6 of 02-Sep-2005, i686-pc-linux-gnu-gcc
gap> RequirePackage("FGA");
true
gap> F := FreeGroup(2);
<free group on the generators [ f1, f2 ]>
### the identity automorphism
gap> x := GroupHomomorphismByImages(F,F,GeneratorsOfGroup(F),GeneratorsOfGroup(F));
[ f1, f2 ] -> [ f1, f2 ]
gap> IsOne(x);
### and GAP freezes.
user interrupt at
...
gap> PackageInfo("fga");
[ rec( PackageName := "FGA", Subtitle := "Free Group Algorithms",
Version := "1.1.0.1", Date := "27/05/2005",
      ArchiveURL :=
"http://www.icm.tu-bs.de/ag_algebra/software/sievers/FGA/FGA-1.1.0.1",
ArchiveFormats := ".tar.gz",
      Persons := [ rec( LastName := "Sievers", FirstNames :=
"Christian", IsAuthor := true, IsMaintainer := true, Email :=
"c.sievers at tu-bs.de",
              PostalAddress := "Christian Sievers\nFachbereich
Mathematik und Informatik\nInstitut Computational
Mathematics\nTechnische Univers\
it\"at Braunschweig\nPockelsstr. 14\nD-38106 Braunschweig,\nGermany",
Place := "Braunschweig", Institution := "TU Braunschweig" ) ],
      Status := "accepted", CommunicatedBy := "Edmund Robertson (St.
Andrews)", AcceptDate := "05/2005",
      README_URL :=
"http://www.icm.tu-bs.de/ag_algebra/software/sievers/FGA/README",
      PackageInfoURL :=
"http://www.icm.tu-bs.de/ag_algebra/software/sievers/FGA/PackageInfo.g",
      AbstractHTML := "The <span class=\"pkgname\">FGA</span> package
installs methods for    computations with finitely generated subgroups
of \
free groups and    provides a presentation for their automorphism groups.",
      PackageWWWHome :=
"http://www.icm.tu-bs.de/ag_algebra/software/sievers/FGA/",
      PackageDoc := [ rec( BookName := "FGA", ArchiveURLSubset := [
"doc", "htm" ], HTMLStart := "htm/chapters.htm",
              PDFFile := "doc/manual.pdf", SixFile :=
"doc/manual.six", LongTitle := "Free Group Algorithms", Autoload :=
true ) ],
      Dependencies := rec( GAP := ">=4.4", NeededOtherPackages := [ 
], SuggestedOtherPackages := [  ], ExternalConditions := [  ] ),
      AvailabilityTest := function( arg ) ... end, Autoload := true,
TestFile := "tst/testall.g",
      Keywords := [ "free groups", "inverse finite automata", "basic
coset enumeration",
          "finite presentation of the automorphism group of a free
group" ], InstallationPath := "/opt/maths/gap4r4/pkg/fga" ) ]


--
Laurent Bartholdi          \  laurent.bartholdi<at>gmail<dot>com
EPFL SB SMA IMB MAD   \    Téléphone: +41 21-6930380
CH-1015 Lausanne, Switzerland \      Fax: +41 21-6930385