diff --git a/doc/chapter_right_modules.xml b/doc/chapter_right_modules.xml
index 5ce03ee..e933a54 100755
--- a/doc/chapter_right_modules.xml
+++ b/doc/chapter_right_modules.xml
@@ -472,7 +472,7 @@ gap> N := RightModuleOverPathAlgebra(A,mat);
the direct sum of the representations contained in the
list L.
In addition three attributes are attached to the
- result, , , .
@@ -540,7 +540,7 @@ gap> N := RightModuleOverPathAlgebra(A,mat);
-
+
Arguments: M -- a path algebra module (PathAlgebraMatModule).
diff --git a/lib/module.gd b/lib/module.gd
index 6aab501..b658b31 100644
--- a/lib/module.gd
+++ b/lib/module.gd
@@ -32,7 +32,7 @@ InstallTrueMethod( IsIndecomposableModule, IsSimpleQPAModule );
DeclareProperty( "IsSemisimpleModule", IsPathAlgebraMatModule );
InstallTrueMethod( IsSemisimpleModule, IsSimpleQPAModule );
DeclareOperation( "DirectSumOfQPAModules", [ IsList] );
-DeclareAttribute( "IsDirectSumOfModules", IsPathAlgebraMatModule );
+DeclareFilter( "IsDirectSumOfModules", IsPathAlgebraMatModule );
DeclareAttribute( "DirectSumProjections", IsPathAlgebraMatModule );
DeclareAttribute( "DirectSumInclusions", IsPathAlgebraMatModule );
DeclareOperation( "SupportModuleElement", [ IsRightAlgebraModuleElement ] );
diff --git a/lib/module.gi b/lib/module.gi
index b4eb70f..0d82eaf 100644
--- a/lib/module.gi
+++ b/lib/module.gi
@@ -1907,7 +1907,7 @@ InstallMethod( DirectSumOfQPAModules,
Add( list_of_incls, RightModuleHomOverAlgebra( L[ i ], direct_sum, maps ) );
od;
- SetIsDirectSumOfModules( direct_sum, true );
+ SetFilterObj( direct_sum, IsDirectSumOfModules );
SetDirectSumProjections( direct_sum, list_of_projs );
SetDirectSumInclusions( direct_sum, list_of_incls );
@@ -1919,25 +1919,6 @@ end
);
-#######################################################################
-##
-#P IsDirectSumOfModules( )
-##
-## is a module over a path algebra. The function checks if the
-## property "IsDirectSumOfModules" is set to true for M, and returns
-## true if it is, and false if it is not. (Note that this is NOT a
-## check for indecomposability.)
-##
-InstallMethod( IsDirectSumOfModules,
- "for a module over a path algebra",
- [ IsPathAlgebraMatModule ], 0,
- function( M )
-
- return "IsDirectSumOfModules" in KnownTruePropertiesOfObject(M);
-
-end
-);
-
#######################################################################
##
#O SupportModuleElement()