outsourced YonedaProjective to FunctorCategories v2020.02.23

PackageInfo.g

@@ -11,7 +11,7 @@ SetPackageInfo( rec(
 PackageName := "CatReps",
 Subtitle := "Representations and cohomology of finite categories",
 Version := Maximum( [
-                   "2020.02.20", ## Mohamed's version
+                   "2020.02.23", ## Mohamed's version
                    ## this line prevents merge conflicts
                    "2020.01.01", ## Tibor's version
                    ## this line prevents merge conflicts
@@ -110,7 +110,7 @@ Dependencies := rec(
                    [ "SubcategoriesForCAP", ">= 2020.02.02" ],
                    [ "MatricesForHomalg", ">= 2020.02.02" ],
                    [ "Toposes", ">= 2020.02.19" ],
-                   [ "FunctorCategories", ">= 2020.02.19" ],
+                   [ "FunctorCategories", ">= 2020.02.23" ],
                    ],
   SuggestedOtherPackages := [ ],
   ExternalConditions := [ ],

gap/CatRepsWithCAP.gd

@@ -115,15 +115,6 @@ DeclareOperation( "EmbeddingOfSubRepresentation",
 DeclareOperation( "WeakDirectSumDecomposition",
         [ IsCapCategoryObjectInHomCategory ] );
 
-#! @Description
-#!  Return Yoneda's projective representation given by the object <A>o</A>,
-#!  i.e., the submodule of the category algebra consisting of all arrows
-#!  starting at <A>o</A>.
-#! @Arguments H, o
-#! @Returns IsCapCategoryObjectInHomCategory
-DeclareOperation( "YonedaProjective",
-        [ IsCapHomCategory, IsCapCategoryObject ] );
-
 ####################################
 #
 #! @Section Tools

gap/CatRepsWithCAP.gi

@@ -193,76 +193,3 @@ InstallMethod( WeakDirectSumDecomposition,
     return List( d, eta -> EmbeddingOfSubRepresentation( eta, F ) );
 
 end );
-
-##
-InstallMethod( YonedaProjective,
-        "for a Hom-category and a CAP object",
-        [ IsCapHomCategory, IsCapCategoryObject ],
-
-  function( CatReps, o )
-    local kq, k, basis_list, A, basis, dimensions, a, arrows, matrices,
-          source, target, dim_source, dim_target, b, b_source, b_target,
-          matrix, b_a_path, b_a, coeffs, yproj;
-
-    kq := Source( CatReps );
-
-    o := Position( SetOfObjects( kq ), o );
-
-    k := CommutativeRingOfLinearCategory( CatReps );
-
-    ## code from QPA2/lib/special-representations.gi
-
-    A := UnderlyingQuiverAlgebra( kq );
-
-    basis_list := BasisOfProjectives( A );
-    basis := basis_list[ o ];
-
-    dimensions := List( basis, Length );
-    arrows := Arrows( QuiverOfAlgebra( A ) );
-    matrices := [ ];
-
-    for a in arrows do
-
-        source := VertexIndex( Source( a ) );
-        target := VertexIndex( Target( a ) );
-
-        dim_source := dimensions[ source ];
-        dim_target := dimensions[ target ];
-
-        if dim_source = 0 or dim_target = 0 then
-
-            matrix := HomalgZeroMatrix( dim_source, dim_target, k );
-
-        else
-
-            b_source := List( basis[ source ], b -> Paths(b)[ 1 ] );
-            b_target := List( basis[ target ], b -> Paths(b)[ 1 ] );
-
-            matrix := [ ];
-
-            for b in b_source do
-                b_a_path := ComposePaths( b, a );
-                b_a := PathAsAlgebraElement( A, b_a_path );
-                coeffs := CoefficientsOfPaths( b_target, b_a );
-                Add( matrix, coeffs );
-            od;
-
-            matrix := HomalgMatrix( matrix, dim_source, dim_target, k );
-
-            matrix := VectorSpaceMorphism( VectorSpaceObject( dim_source, k ), matrix, VectorSpaceObject( dim_target, k ) );
-
-        fi;
-
-        Add( matrices, matrix );
-
-    od;
-
-    dimensions := List( dimensions, dim -> VectorSpaceObject( dim, k ) );
-
-    yproj := AsObjectInHomCategory( kq, dimensions, matrices );
-
-    SetIsProjective( yproj, true );
-
-    return yproj;
-
-end );