fix AmbientTreeiDisplay

Author: grahamknockillaree

lib/CongruenceGroups/congGroups.gd

@@ -1,4 +1,3 @@
-abc:=233;
 
 #############################################################################
 ##
@@ -27,6 +26,14 @@ DeclareOperation("CongruenceSubgroupGamma1", [IsMatrixGroup,IsRingElement]);
 ## important classes of congruence subgroups
 DeclareCategory( "IsHAPCongruenceSubgroup", IsMatrixGroup );
 
+#############################################################################
+##
+## IsHAPConjugatedCongruenceSubgroup( <G> )
+##
+## We create a category of congruence subgroups conjugated by a matrix
+DeclareOperation("IsHAPConjugatedCongruenceSubgroup", [IsHAPCongruenceSubgroup]);
+
+
 #############################################################################
 ##
 ## AmbientGroupOfCongruenceSubgroup( <G> )
@@ -136,10 +143,17 @@ DeclareAttribute( "CosetRepFunction", IsHAPCongruenceSubgroup );
 ##
 ## AmbientTree( <G> )
 ##
-## returns a tree representing the left cosets of G in the ambient group GG 
+## returns a tree representing the left 'cosets' of G in the ambient group GG 
 ## whose construction depends on the given generating set for GG. 
 DeclareAttribute( "AmbientTree", IsHAPCongruenceSubgroup );
 
+############################################################################
+##
+## AmbientTreeDisplay( <G> )
+##
+## displays the tree associated to the congruence subgroup G
+DeclareGlobalFunction("AmbientTreeDisplay");
+
 ############################################################################
 ##
 ## 

lib/CongruenceGroups/congGroups.gi

@@ -28,7 +28,8 @@ InstallMethod( CongruenceSubgroupGamma0, "for integer matrix group and positive
       LevelOfCongruenceSubgroup, n,
           IsHAPPrincipalCongruenceSubgroup, false,
       IsHAPCongruenceSubgroupGamma0, true,  
-      IsHAPCongruenceSubgroupGamma1, false 
+      IsHAPCongruenceSubgroupGamma1, false,
+      IsHAPConjugatedCongruenceSubgroup, false 
       );
      if GG=SL(2,Integers) then
              S:=[[0,-1],[1,0]];; T:=[[1,1],[0,1]]; U:=S*T;
@@ -133,7 +134,8 @@ InstallMethod( PrincipalCongruenceSubgroup,
       LevelOfCongruenceSubgroup, n,
       IsHAPPrincipalCongruenceSubgroup, true,
       IsHAPCongruenceSubgroupGamma0, false,
-      IsHAPCongruenceSubgroupGamma1, false
+      IsHAPCongruenceSubgroupGamma1, false,
+      IsHAPConjugatedCongruenceSubgroup, false
       );
      if GG=SL(2,Integers) then
              S:=[[0,-1],[1,0]];; T:=[[1,1],[0,1]]; U:=S*T;
@@ -445,7 +447,6 @@ InstallMethod( IsSubset,
      RemoveDictionary(leaves,v);
      od;
      #####################################################
-     #fi;
 
      nodesinv:=List(nodes,g->g^-1);