diff --git a/ffi/cs/mcl/mcl.cs b/ffi/cs/mcl/mcl.cs
index 3897bd9..0202a66 100644
--- a/ffi/cs/mcl/mcl.cs
+++ b/ffi/cs/mcl/mcl.cs
@@ -312,10 +312,9 @@ namespace mcl {
             private U128 v0, v1;
             public static Fr One()
             {
-                var fr = new Fr();
-                fr.SetInt(1);
-
-                return fr;
+                var x = new Fr();
+                x.SetInt(1);
+                return x;
             }
             public static Fr Zero() => new Fr();
             public void Clear()
@@ -462,9 +461,9 @@ namespace mcl {
             private U128 v0, v1, v2;
             public static Fp One()
             {
-                var fp = new Fp();
-                fp.SetInt(1);
-                return fp;
+                var x = new Fp();
+                x.SetInt(1);
+                return x;
             }
             public static Fp Zero() => new Fp();
             public void Clear()
@@ -606,11 +605,16 @@ namespace mcl {
         [StructLayout(LayoutKind.Sequential)]
         public struct G1 {
             public Fp x, y, z;
+            public static G1 Zero()
+            {
+                var g1 = new G1();
+                return g1;
+            }
             public void Clear()
             {
                 mclBnG1_clear(ref this);
             }
-            public void SetStr(String s, int ioMode)
+            public void SetStr(string s, int ioMode)
             {
                 if (mclBnG1_setStr(ref this, s, s.Length, ioMode) != 0) {
                     throw new ArgumentException("mclBnG1_setStr:" + s);
@@ -711,11 +715,16 @@ namespace mcl {
         [StructLayout(LayoutKind.Sequential)]
         public struct G2 {
             public Fp2 x, y, z;
+            public static G2 Zero()
+            {
+                var g2 = new G2();
+                return g2;
+            }
             public void Clear()
             {
                 mclBnG2_clear(ref this);
             }
-            public void SetStr(String s, int ioMode)
+            public void SetStr(string s, int ioMode)
             {
                 if (mclBnG2_setStr(ref this, s, s.Length, ioMode) != 0) {
                     throw new ArgumentException("mclBnG2_setStr:" + s);
@@ -788,6 +797,30 @@ namespace mcl {
             {
                 MCL.Mul(ref this, x, y);
             }
+            public static G2 operator -(in G2 x)
+            {
+                var result = new G2();
+                result.Neg(x);
+                return result;
+            }
+            public static G2 operator +(in G2 x, in G2 y)
+            {
+                var z = new G2();
+                z.Add(x, y);
+                return z;
+            }
+            public static G2 operator -(in G2 x, in G2 y)
+            {
+                var z = new G2();
+                z.Sub(x, y);
+                return z;
+            }
+            public static G2 operator *(in G2 x, in Fr y)
+            {
+                var z = new G2();
+                z.Mul(x, y);
+                return z;
+            }
         }
         [StructLayout(LayoutKind.Sequential)]
         public struct GT {
@@ -816,7 +849,7 @@ namespace mcl {
             }
             public string GetStr(int ioMode)
             {
-                StringBuilder sb = new StringBuilder(1024);
+                StringBuilder sb = new StringBuilder(2048);
                 long size = mclBnGT_getStr(sb, sb.Capacity, this, ioMode);
                 if (size == 0) {
                     throw new InvalidOperationException("mclBnGT_getStr:");
diff --git a/ffi/cs/test/test.cs b/ffi/cs/test/test.cs
index 19b0e2f..d3c023b 100644
--- a/ffi/cs/test/test.cs
+++ b/ffi/cs/test/test.cs
@@ -47,6 +47,7 @@ namespace mcl {
         {
             Console.WriteLine("TestFr");
             Fr x = new Fr();
+            assert("x.isZero", x.IsZero());
             x.Clear();
             assert("0", x.GetStr(10) == "0");
             assert("0.IzZero", x.IsZero());
@@ -92,6 +93,7 @@ namespace mcl {
         {
             Console.WriteLine("TestFp");
             Fp x = new Fp();
+            assert("x.isZero", x.IsZero());
             x.Clear();
             assert("0", x.GetStr(10) == "0");
             assert("0.IzZero", x.IsZero());
@@ -137,6 +139,7 @@ namespace mcl {
         {
             Console.WriteLine("TestG1");
             G1 P = new G1();
+            assert("P.isZero", P.IsZero());
             P.Clear();
             assert("P.IsValid", P.IsValid());
             assert("P.IsZero", P.IsZero());
@@ -178,11 +181,14 @@ namespace mcl {
                 MulVec(ref Q, xVec, yVec);
                 assert("mulVecG1", P.Equals(Q));
             }
+            G1 W = G1.Zero();
+            assert("W.IsZero", W.IsZero());
         }
         static void TestG2()
         {
             Console.WriteLine("TestG2");
             G2 P = new G2();
+            assert("P.isZero", P.IsZero());
             P.Clear();
             assert("P is valid", P.IsValid());
             assert("P is zero", P.IsZero());
@@ -224,6 +230,8 @@ namespace mcl {
                 MulVec(ref Q, xVec, yVec);
                 assert("mulVecG2", P.Equals(Q));
             }
+            G2 W = G2.Zero();
+            assert("W.IsZero", W.IsZero());
         }
         static void TestPairing()
         {