diff --git a/gap/semigroups/semigraph.gd b/gap/semigroups/semigraph.gd
index 2cb8b5ab6..69de98a70 100644
--- a/gap/semigroups/semigraph.gd
+++ b/gap/semigroups/semigraph.gd
@@ -10,7 +10,8 @@
 
 DeclareOperation("GraphInverseSemigroup", [IsDigraph]);
 
-DeclareCategory("IsGraphInverseSemigroupElement", IsAssociativeElement);
+DeclareCategory("IsGraphInverseSemigroupElement",
+                 IsAssociativeElement and IsPositionalObjectRep);
 DeclareCategoryCollections("IsGraphInverseSemigroupElement");
 
 DeclareSynonymAttr("IsGraphInverseSubsemigroup",
@@ -38,3 +39,5 @@ DeclareOperation("IndexOfVertexOfGraphInverseSemigroup",
                  [IsGraphInverseSemigroupElement]);
 DeclareAttribute("VerticesOfGraphInverseSemigroup",
                  IsGraphInverseSemigroup);
+DeclareAttribute("EdgesOfGraphInverseSemigroup",
+                 IsGraphInverseSemigroup);
diff --git a/gap/semigroups/semigraph.gi b/gap/semigroups/semigraph.gi
index 1f7d0c3b5..69e2b0f79 100644
--- a/gap/semigroups/semigraph.gi
+++ b/gap/semigroups/semigraph.gi
@@ -282,6 +282,12 @@ function(S)
   return result;
 end);
 
+InstallMethod(EdgesOfGraphInverseSemigroup,
+"for a graph inverse semigroup",
+[IsGraphInverseSemigroup],
+S -> Difference(GeneratorsOfInverseSemigroup(S),
+VerticesOfGraphInverseSemigroup(S)));
+
 InstallMethod(IndexOfVertexOfGraphInverseSemigroup,
 "for a graph inverse semigroup element",
 [IsGraphInverseSemigroupElement],
@@ -291,3 +297,8 @@ function(x)
   fi;
   return x![1][1] - DigraphNrEdges(x![2]);
 end);
+
+InstallMethod(IsWholeFamily,
+"for a subsemigroup of a graph inverse semigroup",
+[IsGraphInverseSubsemigroup],
+S -> Size(ElementsFamily(FamilyObj(S))!.semigroup) = Size(S));