diff --git a/com/google/ortools/constraintsolver/ValCstPair.cs b/com/google/ortools/constraintsolver/ValCstPair.cs
index 4217598710..082e2d5cac 100644
--- a/com/google/ortools/constraintsolver/ValCstPair.cs
+++ b/com/google/ortools/constraintsolver/ValCstPair.cs
@@ -42,4 +42,45 @@ namespace Google.OrTools.ConstraintSolver
       return valCstPair.Cst;
     }
   }
+
+  public class ConstraintAndEquality
+  {
+    public ConstraintAndEquality(IntExpr a, IntExpr b, bool equality)
+    {
+      this.left_ = a;
+      this.right_ = b;
+      this.equality_ = equality;
+    }
+
+    bool IsTrue()
+    {
+      return (object)left_ == (object)right_ ? equality_ : !equality_;
+    }
+
+    Constraint ToConstraint()
+    {
+      return equality_ ?
+          left_.solver().MakeEquality(left_.Var(), right_.Var()) :
+          left_.solver().MakeNonEquality(left_.Var(), right_.Var());
+    }
+
+    public static bool operator true(ConstraintAndEquality eq)
+    {
+      return eq.IsTrue();
+    }
+
+    public static bool operator false(ConstraintAndEquality eq)
+    {
+      return !eq.IsTrue();
+    }
+
+    public static implicit operator Constraint(ConstraintAndEquality eq)
+    {
+      return eq.ToConstraint();
+    }
+
+    private IntExpr left_;
+    private IntExpr right_;
+    private bool equality_;
+  }
 }  // namespace Google.OrTools.ConstraintSolver
diff --git a/constraint_solver/constraint_solver.swig b/constraint_solver/constraint_solver.swig
index 68eeaff60a..fb5389dfde 100644
--- a/constraint_solver/constraint_solver.swig
+++ b/constraint_solver/constraint_solver.swig
@@ -1563,11 +1563,11 @@ namespace operations_research {
   public static ValCstPair operator !=(IntExpr a, long v) {
     return new ValCstPair(a.solver().MakeNonEquality(a.Var(), v));
   }
-  public Constraint Equality(IntExpr b) {
-    return this.solver().MakeEquality(this.Var(), b.Var());
+  public static ConstraintAndEquality operator ==(IntExpr a, IntExpr b) {
+    return new ConstraintAndEquality(a, b, true);
   }
-  public Constraint NonEquality(IntExpr b) {
-    return this.solver().MakeNonEquality(this.Var(), b.Var());
+  public static ConstraintAndEquality operator !=(IntExpr a, IntExpr b) {
+    return new ConstraintAndEquality(a, b, false);
   }
   public static ValCstPair operator >=(IntExpr a, long v) {
     return new ValCstPair(a.solver().MakeGreaterOrEqual(a, v));
diff --git a/csharp/a_round_of_golf.cs b/csharp/a_round_of_golf.cs
index 092613ca96..c3f8a74e1a 100644
--- a/csharp/a_round_of_golf.cs
+++ b/csharp/a_round_of_golf.cs
@@ -117,13 +117,13 @@ public class ARoundOfGolf
     // 2. Mr. Clubb, who isn't Paul, hit several balls into the woods and
     //    scored ten strokes more than the pro-shop clerk.
     solver.Add(Clubb != Paul);
-    solver.Add(score.Element(Clubb).Equality(score.Element(clerk) + 10));
+    solver.Add(score.Element(Clubb) == score.Element(clerk) + 10);
 
     // 3. In some order, Frank and the caddy scored four and seven more
     //    strokes than Mr. Sands.
     solver.Add(caddy != Frank);
     solver.Add(Sands != Frank);
-    solver.Add(caddy.NonEquality(Sands));
+    solver.Add(caddy != Sands);
 
     IntVar b3_a_1 = (score.Element(Sands) + 4).IsEqual(score[Frank]);
     IntVar b3_a_2 = score.Element(caddy).IsEqual(score.Element(Sands) + 7);
diff --git a/csharp/all_interval.cs b/csharp/all_interval.cs
index dbbeb0c1bc..793db46ac0 100644
--- a/csharp/all_interval.cs
+++ b/csharp/all_interval.cs
@@ -47,10 +47,8 @@ public class AllInterval
     solver.Add(diffs.AllDifferent());
 
     for(int k = 0; k < n - 1; k++) {
-      // solver.Add(
-      //     solver.MakeEquality(diffs[k],
-      //         solver.MakeAbs(x[k + 1] - x[k]).Var()));
-      solver.Add(diffs[k].Equality((x[k + 1] - x[k]).Abs()));
+      // solver.Add(diffs[k] == (x[k + 1] - x[k]).Abs());
+      solver.Add(diffs[k] == (x[k + 1] - x[k].Abs()));
     }
 
 
diff --git a/csharp/circuit.cs b/csharp/circuit.cs
index c27df9226e..810719c521 100644
--- a/csharp/circuit.cs
+++ b/csharp/circuit.cs
@@ -42,9 +42,9 @@ public class CircuitTest
     solver.Add(z.AllDifferent());
 
     // put the orbit of x[0] in z[0..n-1]
-    solver.Add(z[0].Equality(x[0]));
+    solver.Add(z[0] == x[0]);
     for(int i = 1; i < n-1; i++) {
-      solver.Add(z[i].Equality(x.Element(z[i-1]).Var()));
+      solver.Add(z[i] == x.Element(z[i-1].Var()));
     }
 
     // z may not be 0 for i < n-1
diff --git a/csharp/circuit2.cs b/csharp/circuit2.cs
index 03f976369b..09101edcb7 100644
--- a/csharp/circuit2.cs
+++ b/csharp/circuit2.cs
@@ -43,9 +43,9 @@ public class CircuitTest2
     solver.Add(z.AllDifferent());
 
     // put the orbit of x[0] in z[0..n-1]
-    solver.Add(z[0].Equality(x[0]));
+    solver.Add(z[0] == x[0]);
     for(int i = 1; i < n-1; i++) {
-      solver.Add(z[i].Equality(x.Element(z[i-1]).Var()));
+      solver.Add(z[i] == x.Element(z[i-1].Var()));
     }
 
     // z may not be 0 for i < n-1
diff --git a/csharp/contiguity_regular.cs b/csharp/contiguity_regular.cs
index cef25b8c27..a22cc5c290 100644
--- a/csharp/contiguity_regular.cs
+++ b/csharp/contiguity_regular.cs
@@ -26,7 +26,7 @@ public class ContiguityRegular
   /*
    * Global constraint regular
    *
-   * This is a translation of MiniZinc's regular constraint (defined in 
+   * This is a translation of MiniZinc's regular constraint (defined in
    * lib/zinc/globals.mzn), via the Comet code refered above.
    * All comments are from the MiniZinc code.
    * """
@@ -52,9 +52,9 @@ public class ContiguityRegular
                         int[,] d,
                         int q0,
                         int[] F) {
-   
 
-   
+
+
     Debug.Assert(Q > 0, "regular: 'Q' must be greater than zero");
     Debug.Assert(S > 0, "regular: 'S' must be greater than zero");
 
@@ -85,8 +85,8 @@ public class ContiguityRegular
     // string).
     int m = 0;
     int n = x.Length;
-    
-    IntVar[] a = solver.MakeIntVarArray(n+1-m, 0,Q+1, "a");   
+
+    IntVar[] a = solver.MakeIntVarArray(n+1-m, 0,Q+1, "a");
     // Check that the final state is in F
     solver.Add(a[a.Length-1].Member(F));
     // First state is q0
@@ -96,10 +96,10 @@ public class ContiguityRegular
       solver.Add(x[i] >= 1);
       solver.Add(x[i] <= S);
       // Determine a[i+1]: a[i+1] == d2[a[i], x[i]]
-      solver.Add(a[i+1].Equality(d2_flatten.Element(((a[i])*S)+(x[i]-1))));
+      solver.Add(a[i+1] == d2_flatten.Element(((a[i]*S)+(x[i]-1))));
 
     }
-        
+
   }
 
 
@@ -115,13 +115,13 @@ public class ContiguityRegular
     int[] accepting_states = {1,2,3};
 
     // The regular expression 0*1*0*
-    int[,] transition_fn =  
+    int[,] transition_fn =
       {
         {1,2}, // state 1 (start): input 0 -> state 1, input 1 -> state 2 i.e. 0*
-        {3,2}, // state 2: 1* 
-        {3,0}, // state 3: 0* 
+        {3,2}, // state 2: 1*
+        {3,0}, // state 3: 0*
       };
-    
+
     MyRegular(solver, x, n_states, input_max, transition_fn,
               initial_state, accepting_states);
 
@@ -139,13 +139,13 @@ public class ContiguityRegular
    * From Global Constraint Catalogue
    * http://www.emn.fr/x-info/sdemasse/gccat/Cglobal_contiguity.html
    * """
-   * Enforce all variables of the VARIABLES collection to be assigned to 0 or 1. 
+   * Enforce all variables of the VARIABLES collection to be assigned to 0 or 1.
    * In addition, all variables assigned to value 1 appear contiguously.
    *
    * Example:
    * (<0, 1, 1, 0>)
    *
-   * The global_contiguity constraint holds since the sequence 0 1 1 0 contains 
+   * The global_contiguity constraint holds since the sequence 0 1 1 0 contains
    * no more than one group of contiguous 1.
    * """
    *
@@ -165,7 +165,7 @@ public class ContiguityRegular
     //
     // Decision variables
     //
-    
+
     // Note: We use 1..2 (instead of 0..1) and subtract 1 in the solution
     IntVar[] reg_input = solver.MakeIntVarArray(n, 1, 2, "reg_input");
 
diff --git a/csharp/crew.cs b/csharp/crew.cs
index bfbad8ca78..ab7ec158ef 100644
--- a/csharp/crew.cs
+++ b/csharp/crew.cs
@@ -37,7 +37,7 @@ public class Crew
    * number of cabin crew, and they have to speak certain languages.
    * Every cabin crew member has two flights off after an attended flight.
    * """
-   * 
+   *
    * Also see http://www.hakank.org/or-tools/crew.pl
    *
    */
@@ -68,7 +68,7 @@ public class Crew
                       "Jean",
                       "Heather",
                       "Juliet"};
- 
+
     int num_persons = names.Length;
 
 
@@ -98,7 +98,7 @@ public class Crew
       {0,1,0,1,1},   // Heather = 18
       {0,1,1,0,0}    // Juliet  = 19
     };
-    
+
 
     //
     // Required number of crew members.
@@ -155,7 +155,7 @@ public class Crew
       }
       nw[p] = tmp.Sum().IsGreater(0);
     }
-    solver.Add(nw.Sum().Equality(num_working));
+    solver.Add(nw.Sum() == num_working);
 
     for(int f = 0; f < num_flights; f++) {
       // size of crew
@@ -164,7 +164,7 @@ public class Crew
         tmp[p] = crew[f,p];
       }
       solver.Add(tmp.Sum() == required_crew[f,0]);
-      
+
       // attributes and requirements
       for(int a = 0; a < 5; a++) {
         IntVar[] tmp2 = new IntVar[num_persons];
@@ -181,7 +181,7 @@ public class Crew
         solver.Add(crew[f,i] + crew[f+1,i] + crew[f+2,i] <= 1);
       }
     }
-    
+
     // extra contraint: all must work at least two of the flights
     /*
     for(int p = 0; p < num_persons; p++) {
@@ -269,7 +269,7 @@ public class Crew
     }
 
     if (args.Length > 1) {
-      min = Convert.ToInt32(args[0]);
+      min = Convert.ToInt32(args[1]);
     }
 
     Solve(n, min);
diff --git a/csharp/crossword.cs b/csharp/crossword.cs
index 20f76cd96a..8da74c7e8f 100644
--- a/csharp/crossword.cs
+++ b/csharp/crossword.cs
@@ -141,11 +141,8 @@ public class Crossword
     //
     for(int I = 0; I < num_overlapping; I++) {
       solver.Add(
-          solver.MakeEquality(
-              A_flat.Element(E[overlapping[I,0]] * word_len +
-                             overlapping[I,1]).Var(),
-              A_flat.Element(E[overlapping[I,2]] * word_len +
-                             overlapping[I,3]).Var()));
+          A_flat.Element(E[overlapping[I,0]] * word_len + overlapping[I,1]) ==
+          A_flat.Element(E[overlapping[I,2]] * word_len + overlapping[I,3]));
     }
 
 
diff --git a/csharp/debruijn.cs b/csharp/debruijn.cs
index 66f41c18c1..e0e68f7dad 100644
--- a/csharp/debruijn.cs
+++ b/csharp/debruijn.cs
@@ -34,7 +34,7 @@ public class DeBruijn
     for(int i = 0; i < len; i++) {
       tmp[i] = (a[i]*(int)Math.Pow(bbase,(len-i-1))).Var();
     }
-     return tmp.Sum().Equality(num);
+     return tmp.Sum() == num;
   }
 
 
@@ -105,18 +105,18 @@ public class DeBruijn
     // elements in binary[i-1]
     for(int i = 1; i < m; i++) {
       for(int j = 1; j < n; j++) {
-        solver.Add(binary[i - 1,j].Equality(binary[i,j - 1]));
+        solver.Add(binary[i - 1,j] == binary[i,j - 1]);
       }
     }
 
     // ... and around the corner
     for(int j = 1; j < n; j++) {
-      solver.Add(binary[m - 1,j].Equality(binary[0,j - 1]));
+      solver.Add(binary[m - 1,j] == binary[0,j - 1]);
     }
 
     // converts binary -> bin_code (de Bruijn sequence)
     for(int i = 0; i < m; i++) {
-      solver.Add(bin_code[i].Equality(binary[i,0]));
+      solver.Add(bin_code[i] == binary[i,0]);
 
     }
 
@@ -127,13 +127,13 @@ public class DeBruijn
     solver.Add(bin_code.Distribute(gcc));
     if (check_same_gcc && m % bbase == 0) {
       for(int i = 1; i < bbase; i++) {
-        solver.Add(gcc[i].Equality(gcc[i - 1]));
+        solver.Add(gcc[i] == gcc[i - 1]);
       }
     }
 
     // symmetry breaking:
     // the minimum value of x should be first
-    // solver.Add(x[0].Equality(x.Min()));
+    // solver.Add(x[0] == x.Min());
 
 
     //
diff --git a/csharp/divisible_by_9_through_1.cs b/csharp/divisible_by_9_through_1.cs
index 303488c4e9..ffa00fe6c2 100644
--- a/csharp/divisible_by_9_through_1.cs
+++ b/csharp/divisible_by_9_through_1.cs
@@ -35,7 +35,7 @@ public class DivisibleBy9Through1
    *
    */
   public static void MyMod(Solver solver, IntVar x, IntVar y, IntVar r) {
-        
+
     long lbx = x.Min();
     long ubx = x.Max();
     long ubx_neg = -ubx;
@@ -44,7 +44,7 @@ public class DivisibleBy9Through1
     int max_x = (int)Math.Max(ubx, lbx_neg);
 
     IntVar d = solver.MakeIntVar(min_x, max_x, "d");
-    
+
     // r >= 0
     solver.Add(r >= 0);
 
@@ -65,7 +65,7 @@ public class DivisibleBy9Through1
 
     // x == y*d+r
     solver.Add(x - (y*d + r) == 0);
-    
+
   }
 
 
@@ -83,7 +83,7 @@ public class DivisibleBy9Through1
     for(int i = 0; i < len; i++) {
       tmp[i] = (a[i]*(int)Math.Pow(bbase,(len-i-1))).Var();
     }
-     return tmp.Sum().Equality(num);
+     return tmp.Sum() == num;
   }
 
   /**
@@ -153,7 +153,7 @@ public class DivisibleBy9Through1
         Console.Write(t[i].Value() + " ");
       }
       Console.WriteLine("\n");
-      
+
       if (bbase != 10) {
         Console.Write("Number base 10: " + t[0].Value());
         Console.Write(" Base " + bbase + ": ");
@@ -161,7 +161,7 @@ public class DivisibleBy9Through1
           Console.Write(digits_str[(int)x[i].Value() + 1]);
         }
         Console.WriteLine("\n");
-        
+
       }
     }
 
diff --git a/csharp/dudeney.cs b/csharp/dudeney.cs
index 0ab49524bf..0ed1ca0d03 100644
--- a/csharp/dudeney.cs
+++ b/csharp/dudeney.cs
@@ -22,7 +22,7 @@ using Google.OrTools.ConstraintSolver;
 
 public class DudeneyNumbers
 {
-  
+
 
   private static Constraint ToNum(IntVar[] a, IntVar num, int bbase) {
     int len = a.Length;
@@ -31,7 +31,7 @@ public class DudeneyNumbers
     for(int i = 0; i < len; i++) {
       tmp[i] = (a[i]*(int)Math.Pow(bbase,(len-i-1))).Var();
     }
-     return tmp.Sum().Equality(num);
+     return tmp.Sum() == num;
   }
 
 
@@ -43,17 +43,17 @@ public class DudeneyNumbers
    * http://cp-is-fun.blogspot.com/2010/09/test-python.html
    * """
    * I discovered yesterday Dudeney Numbers
-   * A Dudeney Numbers is a positive integer that is a perfect cube such that the sum 
-   * of its decimal digits is equal to the cube root of the number. There are only six 
+   * A Dudeney Numbers is a positive integer that is a perfect cube such that the sum
+   * of its decimal digits is equal to the cube root of the number. There are only six
    * Dudeney Numbers and those are very easy to find with CP.
-   * I made my first experience with google cp solver so find these numbers (model below) 
+   * I made my first experience with google cp solver so find these numbers (model below)
    * and must say that I found it very convenient to build CP models in python!
-   * When you take a close look at the line: 
+   * When you take a close look at the line:
    *     solver.Add(sum([10**(n-i-1)*x[i] for i in range(n)]) == nb)
-   * It is difficult to argue that it is very far from dedicated 
+   * It is difficult to argue that it is very far from dedicated
    * optimization languages!
    * """
-   * 
+   *
    * Also see: http://en.wikipedia.org/wiki/Dudeney_number
    *
    */
@@ -77,15 +77,15 @@ public class DudeneyNumbers
     //
     // Constraints
     //
-    solver.Add(nb.Equality(s*s*s)); 
-    solver.Add(x.Sum().Equality(s));
+    solver.Add(nb == s*s*s);
+    solver.Add(x.Sum() == s);
 
     // solver.Add(ToNum(x, nb, 10));
 
     // alternative
     solver.Add((from i in Enumerable.Range(0, n)
                 select (x[i]*(int)Math.Pow(10,n-i-1)).Var()).
-               ToArray().Sum().Equality(nb));
+               ToArray().Sum() == nb);
 
 
     //
diff --git a/csharp/furniture_moving.cs b/csharp/furniture_moving.cs
index b87e2c2723..695a789c5e 100644
--- a/csharp/furniture_moving.cs
+++ b/csharp/furniture_moving.cs
@@ -44,11 +44,11 @@ public class FurnitureMoving
    *
    */
   static void MyCumulative(Solver solver,
-                           IntVar[] s, 
-                           int[] d, 
-                           int[] r, 
+                           IntVar[] s,
+                           int[] d,
+                           int[] r,
                            IntVar b) {
-       
+
     int[] tasks = (from i in Enumerable.Range(0, s.Length)
                    where r[i] > 0 && d[i] > 0
                    select i).ToArray();
@@ -64,7 +64,7 @@ public class FurnitureMoving
       }
       solver.Add((bb.ToArray(typeof(IntVar)) as IntVar[]).Sum() <= b);
     }
-    
+
     // Somewhat experimental:
     // This constraint is needed to constrain the upper limit of b.
     if (b is IntVar) {
@@ -80,7 +80,7 @@ public class FurnitureMoving
    *
    * Marriott & Stukey: 'Programming with constraints', page  112f
    *
-   * The model implements an decomposition of the global constraint 
+   * The model implements an decomposition of the global constraint
    * cumulative (see above).
    *
    * Also see http://www.hakank.org/or-tools/furniture_moving.py
@@ -111,10 +111,10 @@ public class FurnitureMoving
     // Constraints
     //
     for(int i = 0; i < n; i++) {
-      solver.Add(end_times[i].Equality(start_times[i] + duration[i]));
+      solver.Add(end_times[i] == start_times[i] + duration[i]);
     }
 
-    solver.Add(end_time.Equality(end_times.Max()));
+    solver.Add(end_time == end_times.Max());
     MyCumulative(solver, start_times, duration, demand, num_resources);
 
 
@@ -156,7 +156,7 @@ public class FurnitureMoving
       Console.WriteLine("num_resources: {0} end_time: {1}",
                         num_resources.Value(), end_time.Value());
       for(int i = 0; i < n; i++) {
-        Console.WriteLine("Task {0,1}: {1,2} -> {2,2} -> {3,2} (demand: {4})", 
+        Console.WriteLine("Task {0,1}: {1,2} -> {2,2} -> {3,2} (demand: {4})",
                           i,
                           start_times[i].Value(),
                           duration[i],
diff --git a/csharp/grocery.cs b/csharp/grocery.cs
index cf79725775..7268aed59c 100644
--- a/csharp/grocery.cs
+++ b/csharp/grocery.cs
@@ -61,7 +61,7 @@ public class Grocery
     solver.Add(item.Sum() == c);
     solver.Add(item[0] * item[1] * item[2] * item[3] - (c * 100*100*100) == 0);
     // solver.Add(item.Prod() - (c * 100*100*100) == 0);
-    // solver.Add(item.Prod().Equality(c * 100*100*100));
+    // solver.Add(item.Prod() == c * 100*100*100);
 
     // Symmetry breaking
     Decreasing(solver, item);
diff --git a/csharp/map.cs b/csharp/map.cs
index 339dbc202b..bafba79858 100644
--- a/csharp/map.cs
+++ b/csharp/map.cs
@@ -50,15 +50,15 @@ public class Map
     //
     // Constraints
     //
-    solver.Add(color[France].NonEquality(color[Belgium]));
-    solver.Add(color[France].NonEquality(color[Luxembourg]));
-    solver.Add(color[France].NonEquality(color[Germany]));
-    solver.Add(color[Luxembourg].NonEquality(color[Germany]));
-    solver.Add(color[Luxembourg].NonEquality(color[Belgium]));
-    solver.Add(color[Belgium].NonEquality(color[Netherlands]));
-    solver.Add(color[Belgium].NonEquality(color[Germany]));
-    solver.Add(color[Germany].NonEquality(color[Netherlands]));
-    solver.Add(color[Germany].NonEquality(color[Denmark]));
+    solver.Add(color[France] != color[Belgium]);
+    solver.Add(color[France] != color[Luxembourg]);
+    solver.Add(color[France] != color[Germany]);
+    solver.Add(color[Luxembourg] != color[Germany]);
+    solver.Add(color[Luxembourg] != color[Belgium]);
+    solver.Add(color[Belgium] != color[Netherlands]);
+    solver.Add(color[Belgium] != color[Germany]);
+    solver.Add(color[Germany] != color[Netherlands]);
+    solver.Add(color[Germany] != color[Denmark]);
 
     // Symmetry breaking
     solver.Add(color[Belgium] == 1);
diff --git a/csharp/map2.cs b/csharp/map2.cs
index 384dffe0c5..b58eaa1411 100644
--- a/csharp/map2.cs
+++ b/csharp/map2.cs
@@ -67,7 +67,7 @@ public class Map2
     // Constraints
     //
     for(int i = 0; i < neighbours.GetLength(0); i++) {
-      solver.Add(color[neighbours[i,0]].NonEquality(color[neighbours[i,1]]));
+      solver.Add(color[neighbours[i,0]] != color[neighbours[i,1]]);
     }
 
     // Symmetry breaking
diff --git a/csharp/nurse_rostering_regular.cs b/csharp/nurse_rostering_regular.cs
index 8a0ab2a7c9..7017cbaa28 100644
--- a/csharp/nurse_rostering_regular.cs
+++ b/csharp/nurse_rostering_regular.cs
@@ -27,7 +27,7 @@ public class NurseRostering
   /*
    * Global constraint regular
    *
-   * This is a translation of MiniZinc's regular constraint (defined in 
+   * This is a translation of MiniZinc's regular constraint (defined in
    * lib/zinc/globals.mzn), via the Comet code refered above.
    * All comments are from the MiniZinc code.
    * """
@@ -53,9 +53,9 @@ public class NurseRostering
                         int[,] d,
                         int q0,
                         int[] F) {
-   
 
-   
+
+
     Debug.Assert(Q > 0, "regular: 'Q' must be greater than zero");
     Debug.Assert(S > 0, "regular: 'S' must be greater than zero");
 
@@ -86,8 +86,8 @@ public class NurseRostering
     // string).
     int m = 0;
     int n = x.Length;
-    
-    IntVar[] a = solver.MakeIntVarArray(n+1-m, 0,Q+1, "a");   
+
+    IntVar[] a = solver.MakeIntVarArray(n+1-m, 0,Q+1, "a");
     // Check that the final state is in F
     solver.Add(a[a.Length-1].Member(F));
     // First state is q0
@@ -97,10 +97,10 @@ public class NurseRostering
       solver.Add(x[i] >= 1);
       solver.Add(x[i] <= S);
       // Determine a[i+1]: a[i+1] == d2[a[i], x[i]]
-      solver.Add(a[i+1].Equality(d2_flatten.Element(((a[i])*S)+(x[i]-1))));
+      solver.Add(a[i+1] == d2_flatten.Element(((a[i])*S)+(x[i]-1)));
 
     }
-        
+
   }
 
 
@@ -155,7 +155,7 @@ public class NurseRostering
       {6,0,1}, // state 5
       {0,0,1}  // state 6
     };
-    
+
     string[] days = {"d","n","o"}; // for presentation
 
 
@@ -163,7 +163,7 @@ public class NurseRostering
     //
     // Decision variables
     //
-    
+
     // For regular
     IntVar[,] x = new IntVar[num_nurses, num_days];
     IntVar[] x_flat = new IntVar[num_nurses*num_days];
@@ -198,11 +198,11 @@ public class NurseRostering
       MyRegular(solver, reg_input, n_states, input_max, transition_fn,
                 initial_state, accepting_states);
 
-                                            
+
 
     }
 
-    // 
+    //
     // Statistics and constraints for each nurse
     //
     for(int i = 0; i < num_nurses; i++) {
@@ -212,7 +212,7 @@ public class NurseRostering
       for(int j = 0; j < num_days; j++) {
         b[j] = (x[i,j].IsEqual(day_shift) + x[i,j].IsEqual(night_shift)).Var();
       }
-      solver.Add(b.Sum().Equality(nurse_stat[i]));
+      solver.Add(b.Sum() == nurse_stat[i]);
 
       // Each nurse must work between 7 and 10
       // days/nights during this period
@@ -222,7 +222,7 @@ public class NurseRostering
     }
 
 
-    // 
+    //
     // Statistics and constraints for each day
     //
     for(int j = 0; j < num_days; j++) {
@@ -231,7 +231,7 @@ public class NurseRostering
         for(int i = 0; i < num_nurses; i++) {
           b[i] = (x[i,j].IsEqual(t)).Var();
         }
-        solver.Add(b.Sum().Equality(day_stat[j,t]));
+        solver.Add(b.Sum() == day_stat[j,t]);
       }
 
       //
@@ -283,7 +283,7 @@ public class NurseRostering
           occ[v]++;
           Console.Write(days[v] + " ");
         }
-        
+
         Console.Write(" #workdays: {0,2}", nurse_stat[i].Value());
         foreach(int s in valid_shifts) {
           int v = 0;
@@ -293,7 +293,7 @@ public class NurseRostering
           Console.Write("  {0}:{1}", days[s-1], v);
         }
         Console.WriteLine();
-        
+
       }
       Console.WriteLine();
 
diff --git a/csharp/nurse_rostering_transition.cs b/csharp/nurse_rostering_transition.cs
index c8c604dc8a..41efa10e4c 100644
--- a/csharp/nurse_rostering_transition.cs
+++ b/csharp/nurse_rostering_transition.cs
@@ -108,7 +108,7 @@ public class NurseRostering
     //
     // Decision variables
     //
-    
+
     //
     // For TransitionConstraint
     //
@@ -153,7 +153,7 @@ public class NurseRostering
                                                  accepting_states));
     }
 
-    // 
+    //
     // Statistics and constraints for each nurse
     //
     for(int i = 0; i < num_nurses; i++) {
@@ -163,7 +163,7 @@ public class NurseRostering
       for(int j = 0; j < num_days; j++) {
         b[j] = (x[i,j].IsEqual(day_shift) + x[i,j].IsEqual(night_shift)).Var();
       }
-      solver.Add(b.Sum().Equality(nurse_stat[i]));
+      solver.Add(b.Sum() == nurse_stat[i]);
 
       // Each nurse must work between 7 and 10
       // days/nights during this period
@@ -173,7 +173,7 @@ public class NurseRostering
     }
 
 
-    // 
+    //
     // Statistics and constraints for each day
     //
     for(int j = 0; j < num_days; j++) {
@@ -182,7 +182,7 @@ public class NurseRostering
         for(int i = 0; i < num_nurses; i++) {
           b[i] = (x[i,j].IsEqual(t)).Var();
         }
-        solver.Add(b.Sum().Equality(day_stat[j,t]));
+        solver.Add(b.Sum() == day_stat[j,t]);
       }
 
       //
@@ -234,7 +234,7 @@ public class NurseRostering
           occ[v]++;
           Console.Write(days[v] + " ");
         }
-        
+
         Console.Write(" #workdays: {0,2}", nurse_stat[i].Value());
         foreach(int s in valid_shifts) {
           int v = 0;
@@ -244,7 +244,7 @@ public class NurseRostering
           Console.Write("  {0}:{1}", days[s-1], v);
         }
         Console.WriteLine();
-        
+
       }
       Console.WriteLine();
 
diff --git a/csharp/send_more_money.cs b/csharp/send_more_money.cs
index 64a7845233..e047ddb703 100644
--- a/csharp/send_more_money.cs
+++ b/csharp/send_more_money.cs
@@ -46,8 +46,8 @@ public class SendMoreMoney
     // Constraints
     //
     solver.Add(x.AllDifferent());
-    solver.Add((S*1000 + E*100 + N*10 + D + M*1000 + O*100 + R*10 + E).Equality(
-        M*10000 + O*1000 + N*100 + E*10 + Y));
+    solver.Add(S*1000 + E*100 + N*10 + D + M*1000 + O*100 + R*10 + E ==
+               M*10000 + O*1000 + N*100 + E*10 + Y);
 
     solver.Add(S > 0);
     solver.Add(M > 0);
diff --git a/csharp/send_more_money2.cs b/csharp/send_more_money2.cs
index a3a1a3310b..79e64d2e34 100644
--- a/csharp/send_more_money2.cs
+++ b/csharp/send_more_money2.cs
@@ -49,8 +49,8 @@ public class SendMoreMoney
     solver.Add(x.AllDifferent());
 
     /*
-    solver.Add((S*1000 + E*100 + N*10 + D + M*1000 + O*100 + R*10 + E).Equality(
-        M*10000 + O*1000 + N*100 + E*10 + Y));
+    solver.Add(S*1000 + E*100 + N*10 + D + M*1000 + O*100 + R*10 + E ==
+               M*10000 + O*1000 + N*100 + E*10 + Y);
     */
 
     // Here we use scalar product instead.
@@ -61,20 +61,18 @@ public class SendMoreMoney
                                                   new int[] {1000,100,10,1}),
                               solver.MakeScalProd(new IntVar[] {M, O, R, E},
                                                   new int[] {1000,100,10,1}))
-               .Equality(
+                                                  ==
                         solver.MakeScalProd(new IntVar[] {M,O,N,E,Y},
                                             new int[] {10000, 1000, 100, 10, 1}
-                                            ))
+                                            )
                );
     */
-    // Alternative 
+    // Alternative
     int[] s1 = new int[] {1000,100,10,1};
     int[] s2 = new int[] {10000,1000,100,10,1};
     solver.Add(solver.MakeSum(new IntVar[] {S,E,N,D}.ScalProd(s1),
                               new IntVar[] {M,O,R,E}.ScalProd(s1))
-               .Equality(
-                         new IntVar[] {M,O,N,E,Y}.ScalProd(s2))
-               );
+               == new IntVar[] {M,O,N,E,Y}.ScalProd(s2));
 
 
     solver.Add(S > 0);
diff --git a/csharp/ski_assignment.cs b/csharp/ski_assignment.cs
index 0ed55cbfa3..4412214b56 100644
--- a/csharp/ski_assignment.cs
+++ b/csharp/ski_assignment.cs
@@ -79,7 +79,7 @@ public class SkiAssignment
     }
 
     //    IntVar z = solver.MakeIntVar(0, ski_heights.Sum(), "z");
-    //    solver.Add(z_tmp.Sum().Equality(z));
+    //    solver.Add(z_tmp.Sum() == z);
     // The direct cast from IntExpr to IntVar is potentially faster than
     // the above code.
     IntVar z = z_tmp.Sum().VarWithName("z");
diff --git a/csharp/strimko2.cs b/csharp/strimko2.cs
index d54bed9809..1b5a735b80 100644
--- a/csharp/strimko2.cs
+++ b/csharp/strimko2.cs
@@ -44,7 +44,7 @@ public class Strimko2
                       {4,6,6,6,7,7,5},
                       {6,4,6,4,5,5,7},
                       {6,6,4,7,7,7,7}};
-    
+
     // Note: This is 1-based
     int[,] placed = {{2,1,1},
                      {2,3,7},
@@ -59,7 +59,7 @@ public class Strimko2
 
     int n = streams.GetLength(0);
     int num_placed = placed.GetLength(0);
-  
+
     //
     // Decision variables
     //
@@ -74,7 +74,7 @@ public class Strimko2
 
     //
     // Constraints
-    //  
+    //
     // all rows and columns must be unique, i.e. a Latin Square
     for(int i = 0; i < n; i++) {
       IntVar[] row = new IntVar[n];
@@ -87,10 +87,10 @@ public class Strimko2
       solver.Add(row.AllDifferent());
       solver.Add(col.AllDifferent());
     }
-      
+
     // streams
     for(int s = 1; s <= n; s++) {
-      IntVar[] tmp = (from i in Enumerable.Range(0, n) 
+      IntVar[] tmp = (from i in Enumerable.Range(0, n)
                       from j in Enumerable.Range(0, n)
                       where streams[i,j] == s
                       select x[i,j]).ToArray();
@@ -101,8 +101,7 @@ public class Strimko2
     // placed
     for(int i = 0; i <  num_placed; i++) {
       // note: also adjust to 0-based
-      solver.Add(solver.MakeEquality(x[placed[i,0] - 1,placed[i,1] - 1],
-                                     placed[i,2]));
+      solver.Add(x[placed[i,0] - 1,placed[i,1] - 1] ==  placed[i,2]);
     }
 
     //
diff --git a/csharp/to_num.cs b/csharp/to_num.cs
index d4642d2f15..76ff19c649 100644
--- a/csharp/to_num.cs
+++ b/csharp/to_num.cs
@@ -34,7 +34,7 @@ public class ToNumTest
     for(int i = 0; i < len; i++) {
       tmp[i] = (a[i]*(int)Math.Pow(bbase,(len-i-1))).Var();
     }
-     return tmp.Sum().Equality(num);
+     return tmp.Sum() == num;
   }
 
 
diff --git a/csharp/young_tableaux.cs b/csharp/young_tableaux.cs
index 2adf30dd9e..94fdacd986 100644
--- a/csharp/young_tableaux.cs
+++ b/csharp/young_tableaux.cs
@@ -85,7 +85,7 @@ public class YoungTableaux
       for(int j = 0; j < n; j++) {
         b[j] = x[i, j].IsLessOrEqual(n);
       }
-      solver.Add(p[i].Equality(b.Sum()));
+      solver.Add(p[i] == b.Sum());
     }
 
     solver.Add(p.Sum() == n);
diff --git a/csharp/zebra.cs b/csharp/zebra.cs
index 36a5891e5e..f1d0ba6fd5 100644
--- a/csharp/zebra.cs
+++ b/csharp/zebra.cs
@@ -25,7 +25,7 @@ public class NQueens
    *
    * This is a port of the or-tools/Python model zebra.py
    *
-   * 
+   *
    * """
    * This is the zebra problem as invented by Lewis Caroll.
    *
@@ -45,7 +45,7 @@ public class NQueens
    * The Lucky Strike smoker drinks orange juice.
    * The Japanese smokes Parliaments.
    * The Norwegian lives next to the blue house.
-   * 
+   *
    * Who owns a zebra and who drinks water?
    * """
    *
@@ -80,14 +80,14 @@ public class NQueens
     IntVar fox           = solver.MakeIntVar(1, n, "fox");
     IntVar zebra         = solver.MakeIntVar(1, n, "zebra");
     IntVar horse         = solver.MakeIntVar(1, n, "horse");
-    
+
     // Drink
     IntVar tea           = solver.MakeIntVar(1, n, "tea");
     IntVar coffee        = solver.MakeIntVar(1, n, "coffee");
     IntVar water         = solver.MakeIntVar(1, n, "water");
     IntVar milk          = solver.MakeIntVar(1, n, "milk");
     IntVar fruit_juice   = solver.MakeIntVar(1, n, "fruit juice");
-    
+
     // Smoke
     IntVar old_gold      = solver.MakeIntVar(1, n, "old gold");
     IntVar kools         = solver.MakeIntVar(1, n, "kools");
@@ -97,7 +97,7 @@ public class NQueens
 
 
     // for search
-    IntVar[] all_vars = 
+    IntVar[] all_vars =
       {parliaments, kools, chesterfields, lucky_strike, old_gold,
        englishman, spaniard, japanese, ukrainian, norwegian,
        dog, snails, fox, zebra, horse,
@@ -106,38 +106,38 @@ public class NQueens
 
     //
     // Constraints
-    //  
+    //
 
     // Alldifferents
-    solver.Add(new IntVar[] 
+    solver.Add(new IntVar[]
         {red, green, yellow, blue, ivory}.AllDifferent());
-    solver.Add(new IntVar[] 
+    solver.Add(new IntVar[]
         {englishman, spaniard, japanese, ukrainian, norwegian}.AllDifferent());
-    solver.Add(new IntVar[] 
+    solver.Add(new IntVar[]
         {dog, snails, fox, zebra, horse}.AllDifferent());
-    solver.Add(new IntVar[] 
+    solver.Add(new IntVar[]
         {tea, coffee, water, milk, fruit_juice}.AllDifferent());
-    solver.Add(new IntVar[] 
+    solver.Add(new IntVar[]
         {parliaments, kools, chesterfields, lucky_strike, old_gold}.AllDifferent());
 
     //
     // The clues
     //
-    solver.Add(englishman.Equality(red));
-    solver.Add(spaniard.Equality(dog));
-    solver.Add(coffee.Equality(green));
-    solver.Add(ukrainian.Equality(tea));
-    solver.Add(green.Equality(ivory + 1));
-    solver.Add(old_gold.Equality(snails));
-    solver.Add(kools.Equality(yellow));
+    solver.Add(englishman == red);
+    solver.Add(spaniard == dog);
+    solver.Add(coffee == green);
+    solver.Add(ukrainian == tea);
+    solver.Add(green == ivory + 1);
+    solver.Add(old_gold == snails);
+    solver.Add(kools == yellow);
     solver.Add(milk == 3);
     solver.Add(norwegian == 1);
     solver.Add((fox - chesterfields).Abs() == 1);
     solver.Add((horse - kools).Abs() == 1);
-    solver.Add(lucky_strike.Equality(fruit_juice));
-    solver.Add(japanese.Equality(parliaments));
+    solver.Add(lucky_strike == fruit_juice);
+    solver.Add(japanese == parliaments);
     solver.Add((norwegian - blue).Abs() == 1);
-    
+
 
     //
     // Search
@@ -151,11 +151,11 @@ public class NQueens
     IntVar[] p = {englishman, spaniard, japanese, ukrainian, norwegian};
     int[] ix = {0,1,2,3,4};
     while (solver.NextSolution()) {
-      int water_drinker = (from i in ix 
-                           where p[i].Value() == water.Value() 
+      int water_drinker = (from i in ix
+                           where p[i].Value() == water.Value()
                            select i).First();
-      int zebra_owner = (from i in ix 
-                         where p[i].Value() == zebra.Value() 
+      int zebra_owner = (from i in ix
+                         where p[i].Value() == zebra.Value()
                          select i).First();
       Console.WriteLine("The {0} drinks water.", p[water_drinker].ToString());
       Console.WriteLine("The {0} owns the zebra", p[zebra_owner].ToString());