diff --git a/set/OrderedListSet.java b/set/OrderedListSet.java
new file mode 100644
index 0000000..fa7f1c4
--- /dev/null
+++ b/set/OrderedListSet.java
@@ -0,0 +1,140 @@
+package set;
+
+import position.NodePositionList;
+import position.PositionList;
+import utility.DefaultComparator;
+import utility.merge.MergeTemplate;
+
+import java.util.Comparator;
+
+/**
+ * Created with xgiovio.macbookair.
+ * User: xgiovio
+ * Date: 14/05/14
+ * Time: 14:23
+ */
+
+public class OrderedListSet <E> implements Set<E> {
+    private Comparator<E> c;
+    private PositionList<E> L;
+
+
+
+    OrderedListSet() {
+        L = new NodePositionList<E>();
+        c = new DefaultComparator();
+    }
+
+    OrderedListSet(Comparator<E> in_c) {
+        L = new NodePositionList<E>();
+        c = in_c;
+    }
+
+
+
+
+    @Override
+    public int size() {
+        return L.size();
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return L.isEmpty();
+    }
+
+
+
+
+    @Override
+    public Set<E> union(Set<E> B) {
+        new MergeUnion<E>(this.L, ,c);
+    }
+
+    @Override
+    public Set<E> intersect(Set<E> B) {
+        return null;
+    }
+
+    @Override
+    public Set<E> subtract(Set<E> B) {
+        return null;
+    }
+
+
+
+
+
+    //////////////////////// inner class override methods from merge template /////
+
+    protected class MergeUnion<E> extends MergeTemplate<E>{
+
+           public MergeUnion (PositionList<E> A , PositionList<E> B, DefaultComparator<E> c){
+                 super(A,B,c);
+           }
+
+           @Override
+           protected void aIsLess(E a) {
+
+           }
+
+           @Override
+           protected void bIsLess(E b) {
+
+           }
+
+           @Override
+           protected void bothAreEqual(E a, E b) {
+
+           }
+       }
+
+    protected class MergeIntersect<E> extends MergeTemplate<E>{
+
+        public MergeIntersect (PositionList<E> A , PositionList<E> B, DefaultComparator<E> c){
+            super(A,B,c);
+        }
+
+        @Override
+        protected void aIsLess(E a) {
+
+        }
+
+        @Override
+        protected void bIsLess(E b) {
+
+        }
+
+        @Override
+        protected void bothAreEqual(E a, E b) {
+
+        }
+    }
+
+    protected class MergeSubtract<E> extends MergeTemplate<E>{
+
+        public MergeSubtract (PositionList<E> A , PositionList<E> B, DefaultComparator<E> c){
+            super(A,B,c);
+        }
+
+        @Override
+        protected void aIsLess(E a) {
+
+        }
+
+        @Override
+        protected void bIsLess(E b) {
+
+        }
+
+        @Override
+        protected void bothAreEqual(E a, E b) {
+
+        }
+    }
+
+
+
+
+
+}
\ No newline at end of file
diff --git a/set/Set.java b/set/Set.java
new file mode 100644
index 0000000..193ab67
--- /dev/null
+++ b/set/Set.java
@@ -0,0 +1,25 @@
+package set;
+
+/**
+ * Created with xgiovio.macbookair.
+ * User: xgiovio
+ * Date: 14/05/14
+ * Time: 14:18
+ */
+public interface Set<E> {
+    // Restituisce il numero degli elementi nell’insieme
+    public int size();
+
+    // Restituisce true se l’insieme è vuoto
+    public boolean isEmpty();
+
+    // Rimpiazza this con l’unione di this e B
+    public Set<E> union(Set<E> B) ;
+
+    // Rimpiazza this con l’intersezione di this e B
+    public Set<E> intersect(Set<E> B) ;
+
+    // Rimpiazza this con la differenza di this e B
+    public Set <E>subtract(Set <E> B) ;
+
+}
diff --git a/euler_tour/EulerTour.java b/utility/euler_tour/EulerTour.java
similarity index 96%
rename from euler_tour/EulerTour.java
rename to utility/euler_tour/EulerTour.java
index ff03cbb..6ae1963 100644
--- a/euler_tour/EulerTour.java
+++ b/utility/euler_tour/EulerTour.java
@@ -1,4 +1,4 @@
-package euler_tour;
+package utility.euler_tour;
 
 import tree.binarytree.*;
 import position.Position;
diff --git a/euler_tour/expressions/AdditionOperator.java b/utility/euler_tour/expressions/AdditionOperator.java
similarity index 88%
rename from euler_tour/expressions/AdditionOperator.java
rename to utility/euler_tour/expressions/AdditionOperator.java
index ed5192b..9c9b5f7 100644
--- a/euler_tour/expressions/AdditionOperator.java
+++ b/utility/euler_tour/expressions/AdditionOperator.java
@@ -1,4 +1,4 @@
-package euler_tour.expressions;
+package utility.euler_tour.expressions;
 
 /**
  * Created with MONSTER.
diff --git a/euler_tour/expressions/EvaluateExpressionTour.java b/utility/euler_tour/expressions/EvaluateExpressionTour.java
similarity index 89%
rename from euler_tour/expressions/EvaluateExpressionTour.java
rename to utility/euler_tour/expressions/EvaluateExpressionTour.java
index 3803cb7..83edfde 100644
--- a/euler_tour/expressions/EvaluateExpressionTour.java
+++ b/utility/euler_tour/expressions/EvaluateExpressionTour.java
@@ -1,6 +1,6 @@
-package euler_tour.expressions;
+package utility.euler_tour.expressions;
 
-import euler_tour.EulerTour;
+import utility.euler_tour.EulerTour;
 import position.Position;
 import tree.binarytree.BinaryTree;
 
diff --git a/euler_tour/expressions/ExpressionOperator.java b/utility/euler_tour/expressions/ExpressionOperator.java
similarity index 88%
rename from euler_tour/expressions/ExpressionOperator.java
rename to utility/euler_tour/expressions/ExpressionOperator.java
index 9159582..b61774b 100644
--- a/euler_tour/expressions/ExpressionOperator.java
+++ b/utility/euler_tour/expressions/ExpressionOperator.java
@@ -1,4 +1,4 @@
-package euler_tour.expressions;
+package utility.euler_tour.expressions;
 
 /**
  * Created with MONSTER.
diff --git a/euler_tour/expressions/ExpressionTerm.java b/utility/euler_tour/expressions/ExpressionTerm.java
similarity index 86%
rename from euler_tour/expressions/ExpressionTerm.java
rename to utility/euler_tour/expressions/ExpressionTerm.java
index ceb992a..79e5147 100644
--- a/euler_tour/expressions/ExpressionTerm.java
+++ b/utility/euler_tour/expressions/ExpressionTerm.java
@@ -1,4 +1,4 @@
-package euler_tour.expressions;
+package utility.euler_tour.expressions;
 
 /**
  * Created with MONSTER.
diff --git a/euler_tour/expressions/ExpressionVariable.java b/utility/euler_tour/expressions/ExpressionVariable.java
similarity index 90%
rename from euler_tour/expressions/ExpressionVariable.java
rename to utility/euler_tour/expressions/ExpressionVariable.java
index 1dfdee2..4ad58b1 100644
--- a/euler_tour/expressions/ExpressionVariable.java
+++ b/utility/euler_tour/expressions/ExpressionVariable.java
@@ -1,4 +1,4 @@
-package euler_tour.expressions;
+package utility.euler_tour.expressions;
 
 /**
  * Created with MONSTER.
diff --git a/euler_tour/expressions/StringExpressionTour.java b/utility/euler_tour/expressions/StringExpressionTour.java
similarity index 92%
rename from euler_tour/expressions/StringExpressionTour.java
rename to utility/euler_tour/expressions/StringExpressionTour.java
index 701c3ab..381c32b 100644
--- a/euler_tour/expressions/StringExpressionTour.java
+++ b/utility/euler_tour/expressions/StringExpressionTour.java
@@ -1,6 +1,6 @@
-package euler_tour.expressions;
+package utility.euler_tour.expressions;
 
-import euler_tour.EulerTour;
+import utility.euler_tour.EulerTour;
 import position.Position;
 import tree.binarytree.BinaryTree;
 
diff --git a/utility/merge/MergeTemplate.java b/utility/merge/MergeTemplate.java
new file mode 100644
index 0000000..64f298a
--- /dev/null
+++ b/utility/merge/MergeTemplate.java
@@ -0,0 +1,80 @@
+package utility.merge;
+
+import exceptions.BoundaryViolationException;
+import exceptions.EmptyListException;
+import exceptions.InvalidPositionException;
+import position.NodePositionList;
+import position.Position;
+import position.PositionList;
+import utility.DefaultComparator;
+
+import java.util.Comparator;
+import java.util.Iterator;
+
+/**
+ * Created with xgiovio.macbookair.
+ * User: xgiovio
+ * Date: 14/05/14
+ * Time: 14:48
+ */
+public abstract class MergeTemplate<E> {
+
+    PositionList<E> s = new NodePositionList<E>();
+    Comparator<E> c = null;
+
+    public MergeTemplate (PositionList<E> A, PositionList <E> B){
+            this(A,B,new DefaultComparator<E>());
+    }
+
+    public MergeTemplate (PositionList<E> A, PositionList <E> B, Comparator<E> in_c){
+
+        c = in_c;
+        E a,b;
+        Iterator<E> Ait, Bit;
+        Ait = A.iterator();
+        Bit = B.iterator();
+
+        while (!(Ait.hasNext()) && !(Bit.hasNext())) {
+
+            a = Ait.next();
+            b= Bit.next();
+
+            if ( c.compare(a,b) < 0 )
+                aIsLess(a);
+            else if (c.compare(a,b) > 0)
+                bIsLess(b);
+                else // se b = a
+            bothAreEqual(a, b);
+
+        }
+        while (!(Ait.hasNext())) {
+            a = Ait.next();
+            aIsLess(a);
+        }
+        while (!(Bit.hasNext())) {
+            b = Bit.next();
+            bIsLess(b);
+        }
+
+
+    }
+
+
+    abstract protected void aIsLess (E a);
+
+    abstract protected void bIsLess (E b);
+
+    abstract protected void bothAreEqual (E a, E b);
+
+
+    public PositionList<E> getResult () {
+        return s;
+    }
+
+
+
+
+
+
+
+}