diff --git a/applications/test/HashSet/hashSetTest.C b/applications/test/HashSet/hashSetTest.C
index 901d791c21..350a656743 100644
--- a/applications/test/HashSet/hashSetTest.C
+++ b/applications/test/HashSet/hashSetTest.C
@@ -27,6 +27,7 @@ Description
 \*---------------------------------------------------------------------------*/
 
 #include "HashSet.H"
+#include "Map.H"
 
 using namespace Foam;
 
@@ -35,12 +36,46 @@ using namespace Foam;
 
 int main(int argc, char *argv[])
 {
-    HashSet<string> setA(0);
+    wordHashSet setA(0);
+    HashTable<label, word> tableA;
+
+    HashTable<empty> tableB;
+    Map<label> mapA;
 
     setA.insert("kjhk");
     setA.insert("kjhk2");
 
+    tableA.insert("value1", 1);
+    tableA.insert("value2", 2);
+    tableA.insert("value3", 3);
+
+    tableB.insert("value4", empty());
+    tableB.insert("value5", empty());
+    tableB.insert("value6", empty());
+
+    mapA.set(1, 1);
+    mapA.set(2, 2);
+    mapA.set(3, 3);
+    mapA.set(4, 4);
+
     Info<< setA << endl;
+    Info<< tableA << endl;
+    Info<< mapA << endl;
+
+    Info<< "create from HashSet: ";
+    Info<< wordHashSet(setA) << endl;
+    Info<< "create from HashTable<T>: ";
+    Info<< wordHashSet(tableA) << endl;
+    Info<< "create from HashTable<empty>: ";
+    Info<< wordHashSet(tableB) << endl;
+
+    Info<< "create from Map<label>: ";
+    Info<< labelHashSet(mapA) << endl;
+
+    Info<<"combined toc: "
+        << (wordHashSet(setA) | wordHashSet(tableA) | wordHashSet(tableB))
+        << nl;
+
 
     labelHashSet setB(1);
     setB.insert(11);
@@ -71,9 +106,10 @@ int main(int argc, char *argv[])
     setB &= setD;
     Info<< "setB &= setD : " << setB << endl;
 
-    setB += setC;
-    setB -= setD;
-    Info<< "setB += setC -= setD : " << setB << endl;
+    Info<< "setB : " << setB << endl;
+    Info<< "setC : " << setC << endl;
+    Info<< "setD : " << setD << endl;
+    Info<< "setB ^ setC ^ setD : " << (setB ^ setC ^ setD) << endl;
 
     return 0;
 }
diff --git a/src/OpenFOAM/containers/HashTables/HashSet/HashSet.C b/src/OpenFOAM/containers/HashTables/HashSet/HashSet.C
index 6bd0e0200c..66fec2fb1f 100644
--- a/src/OpenFOAM/containers/HashTables/HashSet/HashSet.C
+++ b/src/OpenFOAM/containers/HashTables/HashSet/HashSet.C
@@ -29,6 +29,26 @@ License
 
 #include "HashSet.H"
 
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+template<class Key, class Hash>
+template<class T>
+Foam::HashSet<Key, Hash>::HashSet(const HashTable<T, Key, Hash>& ht)
+:
+    HashTable<empty, Key, Hash>(ht.size())
+{
+    for
+    (
+        typename HashTable<T, Key, Hash>::const_iterator iter = ht.begin();
+        iter != ht.end();
+        ++iter
+    )
+    {
+        insert(iter.key());
+    }
+}
+
+
 // * * * * * * * * * * * * * * * Member Operators  * * * * * * * * * * * * * //
 
 template<class Key, class Hash>
@@ -64,9 +84,9 @@ bool Foam::HashSet<Key, Hash>::operator!=(const HashSet<Key, Hash>& rhs) const
 
 
 template<class Key, class Hash>
-void Foam::HashSet<Key, Hash>::operator+=(const HashSet<Key, Hash>& rhs)
+void Foam::HashSet<Key, Hash>::operator|=(const HashSet<Key, Hash>& rhs)
 {
-    // Add in rhs elements into lhs
+    // Add rhs elements into lhs
     for (const_iterator iter = rhs.begin(); iter != rhs.end(); ++iter)
     {
         insert(iter.key());
@@ -74,6 +94,38 @@ void Foam::HashSet<Key, Hash>::operator+=(const HashSet<Key, Hash>& rhs)
 }
 
 
+template<class Key, class Hash>
+void Foam::HashSet<Key, Hash>::operator&=(const HashSet<Key, Hash>& rhs)
+{
+    // Remove elements not also found in rhs
+    for (iterator iter = this->begin(); iter != this->end(); ++iter)
+    {
+        if (!rhs.found(iter.key()))
+        {
+            erase(iter);
+        }
+    }
+}
+
+
+template<class Key, class Hash>
+void Foam::HashSet<Key, Hash>::operator^=(const HashSet<Key, Hash>& rhs)
+{
+    // Add missed rhs elements, remove duplicate elements
+    for (const_iterator iter = rhs.begin(); iter != rhs.end(); ++iter)
+    {
+        if (found(iter.key()))
+        {
+            erase(iter.key());
+        }
+        else
+        {
+            insert(iter.key());
+        }
+    }
+}
+
+
 template<class Key, class Hash>
 void Foam::HashSet<Key, Hash>::operator-=(const HashSet<Key, Hash>& rhs)
 {
@@ -85,23 +137,51 @@ void Foam::HashSet<Key, Hash>::operator-=(const HashSet<Key, Hash>& rhs)
 }
 
 
+// * * * * * * * * * * * * * * * Friend Operators  * * * * * * * * * * * * * //
+
+/* * * * * * * * * * * * * * * * Global operators  * * * * * * * * * * * * * */
+
 template<class Key, class Hash>
-void Foam::HashSet<Key, Hash>::operator&=(const HashSet<Key, Hash>& rhs)
+Foam::HashSet<Key, Hash>
+Foam::operator|
+(
+    const HashSet<Key, Hash>& hash1,
+    const HashSet<Key, Hash>& hash2
+)
 {
-    // Remove elements not found in rhs as well
-    for (iterator iter = this->begin(); iter != this->end(); ++iter)
-    {
-        if (!rhs.found(iter.key()))
-        {
-            erase(iter);
-        }
-    }
+    HashSet<Key, Hash> out(hash1);
+    out |= hash2;
+    return out;
 }
 
 
-// * * * * * * * * * * * * * * * Friend Operators  * * * * * * * * * * * * * //
+template<class Key, class Hash>
+Foam::HashSet<Key, Hash>
+Foam::operator&
+(
+    const HashSet<Key, Hash>& hash1,
+    const HashSet<Key, Hash>& hash2
+)
+{
+    HashSet<Key, Hash> out(hash1);
+    out &= hash2;
+    return out;
+}
 
 
+template<class Key, class Hash>
+Foam::HashSet<Key, Hash>
+Foam::operator^
+(
+    const HashSet<Key, Hash>& hash1,
+    const HashSet<Key, Hash>& hash2
+)
+{
+    HashSet<Key, Hash> out(hash1);
+    out ^= hash2;
+    return out;
+}
+
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 #endif
diff --git a/src/OpenFOAM/containers/HashTables/HashSet/HashSet.H b/src/OpenFOAM/containers/HashTables/HashSet/HashSet.H
index 4a6fd3de90..4c043b1dd5 100644
--- a/src/OpenFOAM/containers/HashTables/HashSet/HashSet.H
+++ b/src/OpenFOAM/containers/HashTables/HashSet/HashSet.H
@@ -106,22 +106,25 @@ public:
             HashTable<empty, Key, Hash>(hs)
         {}
 
+        //- Construct from table of contents of the HashTable
+        template<class T>
+        HashSet(const HashTable<T, Key, Hash>& ht);
 
     // Member Functions
 
         // Edit
 
-            //- Insert a new entry
-            bool insert(const Key& key)
-            {
-                return HashTable<empty, Key, Hash>::insert(key, empty());
-            }
+        //- Insert a new entry
+        bool insert(const Key& key)
+        {
+            return HashTable<empty, Key, Hash>::insert(key, empty());
+        }
 
-            //- Same as insert (cannot overwrite empty content)
-            bool set(const Key& key)
-            {
-                return HashTable<empty, Key, Hash>::insert(key, empty());
-            }
+        //- Same as insert (cannot overwrite empty content)
+        bool set(const Key& key)
+        {
+            return HashTable<empty, Key, Hash>::insert(key, empty());
+        }
 
 
     // Member Operators
@@ -134,18 +137,56 @@ public:
         bool operator!=(const HashSet<Key, Hash>&) const;
 
 
-        //- Add entries listed in the given HashSet to this HashSet
-        void operator+=(const HashSet<Key, Hash>&);
-
-        //- Remove entries listed in the given HashSet from this HashSet
-        void operator-=(const HashSet<Key, Hash>&);
+        //- Combine entries from HashSets
+        void operator|=(const HashSet<Key, Hash>&);
 
         //- Only retain entries found in both HashSets
         void operator&=(const HashSet<Key, Hash>&);
 
+        //- Only retain unique entries (xor)
+        void operator^=(const HashSet<Key, Hash>&);
+
+        //- Add entries listed in the given HashSet to this HashSet
+        inline void operator+=(const HashSet<Key, Hash>& rhs)
+        {
+            this->operator|=(rhs);
+        }
+
+        //- Remove entries listed in the given HashSet from this HashSet
+        void operator-=(const HashSet<Key, Hash>&);
+
 };
 
 
+// Global Operators
+
+//- Combine entries from HashSets
+template<class Key, class Hash>
+HashSet<Key,Hash> operator|
+(
+    const HashSet<Key,Hash>& hash1,
+    const HashSet<Key,Hash>& hash2
+);
+
+
+//- Create a HashSet that only contains entries found in both HashSets
+template<class Key, class Hash>
+HashSet<Key,Hash> operator&
+(
+    const HashSet<Key,Hash>& hash1,
+    const HashSet<Key,Hash>& hash2
+);
+
+
+//- Create a HashSet that only contains unique entries (xor)
+template<class Key, class Hash>
+HashSet<Key,Hash> operator^
+(
+    const HashSet<Key,Hash>& hash1,
+    const HashSet<Key,Hash>& hash2
+);
+
+
 //- A HashSet with word keys.
 typedef HashSet<> wordHashSet;