GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it
#############################################################################
##
## GradedModuleMap.gd Graded Modules package
##
## Copyright 2010, Mohamed Barakat, University of Kaiserslautern
## Markus Lange-Hegermann, RWTH Aachen
##
## Declaration stuff for graded module homomorphisms .
##
#############################################################################
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#
# categories:
#
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# two new categories:
## <#GAPDoc Label="IsHomalgMap">
## <ManSection>
## <Filt Type="Category" Arg="phi" Name="IsHomalgMap"/>
## <Returns><C>true</C> or <C>false</C></Returns>
## <Description>
## The &GAP; category of graded &homalg; maps. <P/>
## (It is a subcategory of the &GAP; category
## <C>IsHomalgMap</C>.)
## <Listing Type="Code"><![CDATA[
DeclareCategory( "IsHomalgGradedMap",
IsHomalgMap );
## ]]></Listing>
## </Description>
## </ManSection>
## <#/GAPDoc>
## <#GAPDoc Label="IsHomalgSelfMap">
## <ManSection>
## <Filt Type="Category" Arg="phi" Name="IsHomalgSelfMap"/>
## <Returns><C>true</C> or <C>false</C></Returns>
## <Description>
## The &GAP; category of graded &homalg; self-maps. <P/>
## (It is a subcategory of the &GAP; categories
## <C>IsHomalgGradedMap</C>, <C>IsHomalgEndomorphism</C> and <C>IsHomalgSelfMap</C>.)
## <Listing Type="Code"><![CDATA[
DeclareCategory( "IsHomalgGradedSelfMap",
IsHomalgGradedMap and
IsHomalgEndomorphism and
IsHomalgSelfMap );
## ]]></Listing>
## </Description>
## </ManSection>
## <#/GAPDoc>
####################################
#
# properties:
#
####################################
##
DeclareAttribute( "CastelnuovoMumfordRegularity",
IsHomalgGradedMap );
DeclareAttribute( "MaximalIdealAsLeftMorphism",
IsHomalgGradedRing );
DeclareAttribute( "MaximalIdealAsRightMorphism",
IsHomalgGradedRing );
DeclareAttribute( "UnderlyingMorphism",
IsHomalgGradedMap );
####################################
#
# global functions and operations:
#
####################################
DeclareOperation( "GradedVersionOfMorphismAid",
[ IsHomalgMap, IsHomalgGradedModule ] );
DeclareOperation( "NormalizeGradedMorphism",
[ IsHomalgGradedMap ] );
DeclareOperation( "GradedMap",
[ IsHomalgMatrix, IsObject, IsObject ] );
DeclareOperation( "GradedMap",
[ IsHomalgMatrix, IsObject, IsObject, IsString ] );
DeclareOperation( "GradedMap",
[ IsHomalgMatrix, IsObject, IsObject, IsHomalgRing ] );
DeclareOperation( "GradedMap",
[ IsHomalgMatrix, IsObject, IsObject, IsString, IsHomalgRing ] );
DeclareOperation( "GradedMap",
[ IsHomalgMap, IsHomalgRing ] );
DeclareOperation( "GradedMap",
[ IsHomalgMap, IsObject, IsObject ] );
DeclareOperation( "GradedMap",
[ IsHomalgMap, IsObject, IsObject, IsHomalgRing ] );
DeclareOperation( "GradedZeroMap",
[ IsHomalgGradedModule, IsHomalgGradedModule ] );
# constructors:
# basic operations