split operation GroupoidInnerAutomorphism

Author: cdwensley

CHANGES.md

@@ -1,6 +1,7 @@
 # CHANGES to the 'groupoids' package 
 
-## Version 1.79 for GAP 4.14.0 (10/09/25)
+## Version 1.79 for GAP 4.14.0 (11/09/25)
+ * (11/09/25) added operation GroupoidInnerAutomorphismNormalSubgroupoid
  * (10/09/25) added new release mechanism file .github/workflows/release.yml 
  * (22/07/25) revised code and examples of GroupoidInnerAutomorphism
  * (21/07/25) added GroupoidAutomorphismByNtuple(NC)

PackageInfo.g

@@ -9,7 +9,7 @@ SetPackageInfo( rec(
 PackageName := "groupoids",
 Subtitle := "Calculations with finite groupoids and their homomorphisms",
 Version := "1.79",
-Date := "10/09/2025", # dd/mm/yyyy format
+Date := "11/09/2025", # dd/mm/yyyy format
 License := "GPL-2.0-or-later",
 
 Persons := [

doc/gpdaut.xml

@@ -127,7 +127,7 @@ ray images: [ (), (1,3,2), (1,3,4) ]
 <ManSection>
    <Oper Name="GroupoidInnerAutomorphism" 
          Arg="gpd, arrow" />
-   <Oper Name="GroupoidInnerAutomorphism" 
+   <Oper Name="GroupoidInnerAutomorphismNormalSubgroupoid" 
          Arg="gpd, subgpd, arrow" />
 <Description>
 <Index>inner automorphism</Index> 
@@ -172,7 +172,7 @@ the inner automorphism by <M>a</M> may be applied to <M>N</M>.
 gap> Nk4 := SubgroupoidBySubgroup( Ha4, k4 );;
 gap> SetName( Nk4, "Nk4" );
 gap> e4 := Arrow( Ha4, (1,2)(3,4), -14, -13 );;
-gap> inn2 := GroupoidInnerAutomorphism( Ha4, Nk4, e4 );;
+gap> inn2 := GroupoidInnerAutomorphismNormalSubgroupoid( Ha4, Nk4, e4 );;
 gap> Display( inn2 );
 homomorphism to single piece groupoid: Nk4 -> Nk4
 root group homomorphism:

lib/gpdaut.gd

@@ -58,9 +58,12 @@ DeclareOperation( "GroupoidAutomorphismByRayShifts",
 ############################################################################# 
 ## 
 #O  GroupoidInnerAutomorphism( <gpd>, <arr> )
+#O  GroupoidInnerAutomorphismNormalSubgroupoid( <gpd>, <nsgpd>, <arr> )
 ##
 DeclareOperation( "GroupoidInnerAutomorphism", 
     [ IsGroupoid, IsGroupoidElement ] ); 
+DeclareOperation( "GroupoidInnerAutomorphismNormalSubgroupoid", 
+    [ IsGroupoid, IsGroupoid, IsGroupoidElement ] ); 
 
 ############################################################################# 
 ## 

lib/gpdaut.gi

@@ -259,6 +259,7 @@ end );
 #############################################################################
 ##
 #M  GroupoidInnerAutomorphism 
+#M  GroupoidInnerAutomorphismNormalSubgroupoid
 ##
 InstallMethod( GroupoidInnerAutomorphism, 
     "for a groupoid and an element", true,
@@ -297,14 +298,14 @@ function( gpd, e )
     return GroupoidAutomorphismByGroupAutosNC( gpd, auts ); 
 end );
 
-InstallOtherMethod( GroupoidInnerAutomorphism, 
+InstallMethod( GroupoidInnerAutomorphismNormalSubgroupoid, 
     "for a groupoid, a subgroupoid, and an element", true, 
     [ IsGroupoid and IsSinglePieceDomain, IsGroupoid, IsGroupoidElement ], 0,
 function( gpd, sub, e ) 
 
     local obs, gens, images, pieces, n, homs, oims, i, p, o, q, h; 
 
-    Info( InfoGroupoids, 3, "GroupoidInnerAutomorphism for a subgroupoid" ); 
+    Info( InfoGroupoids, 3, "GroupoidInnerAutomorphismNormalSubgroupoid" ); 
     if not IsWideSubgroupoid( gpd, sub ) then 
         Error( "sub is not a subgroupoid of gpd" ); 
     fi;
@@ -1069,7 +1070,7 @@ function( gpd )
     local aut, map, act;
 
     aut := AutomorphismGroupOfGroupoid( gpd );
-    map := function(a) return GroupoidInnerAutomorphism(gpd,a); end;
+    map := function(a) return GroupoidInnerAutomorphism( gpd, a ); end;
     act := rec(); 
     ObjectifyWithAttributes( act, GroupoidActionType, 
         Source, gpd,
@@ -1099,7 +1100,9 @@ function( gpd, sub )
         Error( "invalid subgroupoid sub" );
     fi;
     aut := AutomorphismGroupOfGroupoid( sub );
-    map := function(a) return GroupoidInnerAutomorphism(gpd,sub,a); end;
+    map := function(a) 
+               return GroupoidInnerAutomorphismNormalSubgroupoid(gpd,sub,a);
+           end;
     act := rec(); 
     ObjectifyWithAttributes( act, GroupoidActionType, 
         Source, gpd,

tst/manual/gpdaut.tst

@@ -106,7 +106,7 @@ gap> d5 := ImageElm( inn1, d4 );
 gap> Nk4 := SubgroupoidBySubgroup( Ha4, k4 );;
 gap> SetName( Nk4, "Nk4" );
 gap> e4 := Arrow( Ha4, (1,2)(3,4), -14, -13 );;
-gap> inn2 := GroupoidInnerAutomorphism( Ha4, Nk4, e4 );;
+gap> inn2 := GroupoidInnerAutomorphismNormalSubgroupoid( Ha4, Nk4, e4 );;
 gap> Display( inn2 );
 homomorphism to single piece groupoid: Nk4 -> Nk4
 root group homomorphism:
@@ -117,7 +117,7 @@ ray images: [ (), (), (1,2)(3,4) ]
 
 gap> Ma4 := MaximalDiscreteSubgroupoid( Ha4 );;
 gap> SetName( Ma4, "Ma4" );
-gap> inn3 := GroupoidInnerAutomorphism( Ha4, Ma4, e4 );;
+gap> inn3 := GroupoidInnerAutomorphismNormalSubgroupoid( Ha4, Ma4, e4 );;
 gap> Display( inn3 );
 homogeneous discrete groupoid mapping: [ Ma4 ] -> [ Ma4 ]
 images of objects: [ -13, -14, -12 ]