GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it
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## GradedRingMap.gd GradedRingForHomalg package Mohamed Barakat
## Markus Lange-Hegermann
##
## Copyright 2010, Mohamed Barakat, University of Kaiserslautern
## Markus Lange-Hegermann, RWTH-Aachen University
##
## Declarations of procedures for graded rings.
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#
# categories:
#
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# two new GAP-categories:
## <#GAPDoc Label="IsHomalgGradedRingMap">
## <ManSection>
## <Filt Type="Category" Arg="phi" Name="IsHomalgGradedRingMap"/>
## <Returns><C>true</C> or <C>false</C></Returns>
## <Description>
## The &GAP; category of ring maps.
## <Listing Type="Code"><![CDATA[
DeclareCategory( "IsHomalgGradedRingMap",
IsHomalgRingMap );
## ]]></Listing>
## </Description>
## </ManSection>
## <#/GAPDoc>
##
## <#GAPDoc Label="IsHomalgGradedRingSelfMap">
## <ManSection>
## <Filt Type="Category" Arg="phi" Name="IsHomalgGradedRingSelfMap"/>
## <Returns><C>true</C> or <C>false</C></Returns>
## <Description>
## The &GAP; category of ring self-maps.
## <Listing Type="Code"><![CDATA[
DeclareCategory( "IsHomalgGradedRingSelfMap",
IsHomalgRingSelfMap and
IsHomalgGradedRingMap );
## ]]></Listing>
## </Description>
## </ManSection>
## <#/GAPDoc>
##