diff --git a/csharp/Lib/Units/Angle.generated.cs b/csharp/Lib/Units/Angle.generated.cs
index ad576594a..f2317f977 100644
--- a/csharp/Lib/Units/Angle.generated.cs
+++ b/csharp/Lib/Units/Angle.generated.cs
@@ -18,25 +18,24 @@ public readonly partial struct Angle
     public static T operator *(T t, Decimal scalar) => new T(scalar * t.Value);
     public static T operator /(T t, Decimal scalar) => new T(t.Value / scalar);
     
-    // addition
+    // parallel
     
     #if Sum
     
-    public static T operator +(T left, T right) => new T(left.Value + right.Value);
-    public static T operator -(T left, T right) => new T(left.Value - right.Value);
+    public static T operator |(T left, T right) => new T(left.Value + right.Value);
     public static T operator -(T t)             => new T(-t.Value);
     
     #elif Mean
     
-    public static T operator +(T left, T right) => new T((left.Value + right.Value)/2m);
+    public static T operator |(T left, T right) => new T((left.Value + right.Value)/2m);
     
     #elif Equal
     
-    public static T operator +(T left, T right)
+    public static T operator |(T left, T right)
     {
         var d = Max(Abs(left.Value), Abs(right.Value));
 
-        if (d != 0m)
+        if (d == 0m)
             return new T(0m);
 
         var relativeError = Abs(left.Value - right.Value) / d;
diff --git a/csharp/Lib/Units/ApparentPower.generated.cs b/csharp/Lib/Units/ApparentPower.generated.cs
index cfa6174ed..0775151c9 100644
--- a/csharp/Lib/Units/ApparentPower.generated.cs
+++ b/csharp/Lib/Units/ApparentPower.generated.cs
@@ -18,25 +18,24 @@ public readonly partial struct ApparentPower
     public static T operator *(T t, Decimal scalar) => new T(scalar * t.Value);
     public static T operator /(T t, Decimal scalar) => new T(t.Value / scalar);
     
-    // addition
+    // parallel
     
     #if Sum
     
-    public static T operator +(T left, T right) => new T(left.Value + right.Value);
-    public static T operator -(T left, T right) => new T(left.Value - right.Value);
+    public static T operator |(T left, T right) => new T(left.Value + right.Value);
     public static T operator -(T t)             => new T(-t.Value);
     
     #elif Mean
     
-    public static T operator +(T left, T right) => new T((left.Value + right.Value)/2m);
+    public static T operator |(T left, T right) => new T((left.Value + right.Value)/2m);
     
     #elif Equal
     
-    public static T operator +(T left, T right)
+    public static T operator |(T left, T right)
     {
         var d = Max(Abs(left.Value), Abs(right.Value));
 
-        if (d != 0m)
+        if (d == 0m)
             return new T(0m);
 
         var relativeError = Abs(left.Value - right.Value) / d;
diff --git a/csharp/Lib/Units/Composite/Ac1Phase.cs b/csharp/Lib/Units/Composite/Ac1Phase.cs
index e48807866..d7cfc20e7 100644
--- a/csharp/Lib/Units/Composite/Ac1Phase.cs
+++ b/csharp/Lib/Units/Composite/Ac1Phase.cs
@@ -1,25 +1,28 @@
+
 using System.Diagnostics.CodeAnalysis;
 
 namespace InnovEnergy.Lib.Units.Composite;
 
-public record Ac1Phase
-(
-    Voltage Voltage,
-    Current Current,
-    Angle Phi,
-    Frequency Frequency
-) 
-    : AcPhase(Voltage, Current, Phi)
+public record Ac1Phase : AcPhase
 {
+    public required Frequency Frequency { get; init; }
 
     [SuppressMessage("ReSharper", "RedundantCast")]
-    public static Ac1Phase operator +(Ac1Phase left, Ac1Phase right)
+    public static Ac1Phase operator |(Ac1Phase left, Ac1Phase right)
     {
-        var f = (left.Frequency + right.Frequency) / 2m;  // TODO: check that l & r approximately equal
-        var acPhase = (AcPhase)left + (AcPhase)right;
-        return new Ac1Phase(acPhase.Voltage, acPhase.Current, acPhase.Phi, f);
+        var f = left.Frequency | right.Frequency;
+        var p = (AcPhase)left | (AcPhase)right;
+
+        return new Ac1Phase
+        {
+            Frequency = f,
+            Current = p.Current,
+            Voltage = p.Voltage,
+            Phi = p.Phi
+        };
     }
     
+
 }
 
 
diff --git a/csharp/Lib/Units/Composite/Ac3Phase.cs b/csharp/Lib/Units/Composite/Ac3Phase.cs
index a5788e452..d73f8e9e4 100644
--- a/csharp/Lib/Units/Composite/Ac3Phase.cs
+++ b/csharp/Lib/Units/Composite/Ac3Phase.cs
@@ -1,25 +1,22 @@
+using InnovEnergy.Lib.Utils;
 using static DecimalMath.DecimalEx;
 
 namespace InnovEnergy.Lib.Units.Composite;
 
-public record Ac3Phase(AcPhase L1, AcPhase L2, AcPhase L3, Frequency Frequency)
+public record Ac3Phase
 {
+    public required AcPhase   L1        { get; init; }
+    public required AcPhase   L2        { get; init; }
+    public required AcPhase   L3        { get; init; }
+    public required Frequency Frequency { get; init; }
+    
     public ApparentPower ApparentPower => L1.ApparentPower + L2.ApparentPower + L3.ApparentPower;
     public ReactivePower ReactivePower => L1.ReactivePower + L2.ReactivePower + L3.ReactivePower;
     public Power         ActivePower   => L1.ActivePower   + L2.ActivePower   + L3.ActivePower;
+    public Angle         Phi           => ATan2(ReactivePower, ActivePower);
 
-    public Angle Phi => ATan2(ReactivePower, ActivePower);
-    
-    
-    public static Ac3Phase operator +(Ac3Phase left, Ac3Phase right)
-    {
-        var f = (left.Frequency + right.Frequency) / 2m;  // TODO: check that l & r approximately equal
+    public static Ac3Phase operator |(Ac3Phase left, Ac3Phase right) => OpParallel(left, right);
+    private static readonly Func<Ac3Phase, Ac3Phase, Ac3Phase> OpParallel = "|".CreateBinaryOpForProps<Ac3Phase>();
 
-        var l1 = left.L1 + right.L1;
-        var l2 = left.L2 + right.L2;
-        var l3 = left.L3 + right.L3;
-
-        return new Ac3Phase(l1, l2, l3, f);
-    }
     
 }
\ No newline at end of file
diff --git a/csharp/Lib/Units/Composite/AcPhase.cs b/csharp/Lib/Units/Composite/AcPhase.cs
index 70cd952b2..426091fbc 100644
--- a/csharp/Lib/Units/Composite/AcPhase.cs
+++ b/csharp/Lib/Units/Composite/AcPhase.cs
@@ -3,17 +3,23 @@ using static DecimalMath.DecimalEx;
 namespace InnovEnergy.Lib.Units.Composite;
 
 
-public record AcPhase : Phase
+public record AcPhase : IPhase
 {
-    public AcPhase(Voltage voltage, Current current, Angle phi) : base(voltage, current)
+    private readonly Voltage _Voltage;
+    public required Voltage Voltage
     {
-        if (voltage < 0) throw new ArgumentException("RMS value cannot be negative", nameof(voltage));
-        if (current < 0) throw new ArgumentException("RMS value cannot be negative", nameof(current));
-        
-        Phi = phi;
+        get  => _Voltage;
+        init => _Voltage = value >= 0 ? value : throw new ArgumentException("RMS value cannot be negative");
     }
 
-    public Angle Phi { get; }
+    private readonly Current _Current;
+    public required Current Current
+    {
+        get  => _Current;
+        init => _Current = value >= 0 ? value : throw new ArgumentException("RMS value cannot be negative");
+    }
+    
+    public required Angle   Phi { get; init; }
     
     public ApparentPower ApparentPower => Voltage.Value * Current.Value ;
     public Power         ActivePower   => ApparentPower.Value * PowerFactor;
@@ -21,34 +27,40 @@ public record AcPhase : Phase
     public Decimal       PowerFactor   => Cos(Phi);
     
     
-    public static AcPhase operator +(AcPhase left, AcPhase right)
+    public static AcPhase operator |(AcPhase left, AcPhase right)
     {
         // the Voltages of two phases are expected to be in phase and equal
 
-        var v = (left.Voltage + right.Voltage) / 2m;  // TODO: check that l & r approximately equal
+        var v = left.Voltage | right.Voltage;  
         
         // currents (RMS) can be different and out of phase 
         // https://www.johndcook.com/blog/2020/08/17/adding-phase-shifted-sine-waves/
         
         // IF
-        // left(t) = ILeft sin(ωt)
+        // left(t)  = ILeft sin(ωt)
         // right(t) = IRight sin(ωt + φ).
-        // sum(t) = left(t) + right(t) = ISum sin(ωt + ψ).
-        // THEN
+        // sum(t)   = left(t) + right(t) = ISum sin(ωt + ψ).
         
+        // THEN
         // ψ = arctan( IRight * sin(φ) / (ILeft + IRight cos(φ)) ).
         // C = IRight * sin(φ) / sin(ψ).
                 
-        // in this calc left(t) has zero phase shift.
+        // in this calculation left(t) has zero phase shift.
         // we can shift both waves by -left.Phi, so
         // φ := right.phi - left.phi
 
 
-        var phi = right.Phi - left.Phi;
-
+        var phi    = right.Phi - left.Phi;
         var phiSum = ATan2(right.Current * Sin(phi), left.Current + right.Current * Cos(phi));
         var iSum   = right.Current * Sin(phi) / Sin(phiSum);
 
-        return new AcPhase(v, iSum, phiSum);
+        return new AcPhase
+        {
+           Voltage = v,
+           Current = iSum,
+           Phi     = phiSum
+        };
     }
+
+    
 }
\ No newline at end of file
diff --git a/csharp/Lib/Units/Composite/DcPhase.cs b/csharp/Lib/Units/Composite/DcPhase.cs
index af6d1049a..2d0b24b68 100644
--- a/csharp/Lib/Units/Composite/DcPhase.cs
+++ b/csharp/Lib/Units/Composite/DcPhase.cs
@@ -1,15 +1,16 @@
+using InnovEnergy.Lib.Utils;
+
 namespace InnovEnergy.Lib.Units.Composite;
 
-public record DcPhase(Voltage Voltage, Current Current) : Phase(Voltage, Current)
+public record DcPhase : IPhase
 {
-   public Power Power => Current * Voltage;
-
-   public static DcPhase operator +(DcPhase left, DcPhase right)
-   {
-      var v = (left.Voltage + right.Voltage) / 2m;
-      var i = left.Current + right.Current;
-
-      return new DcPhase(v, i);
-   }
+   public required Voltage Voltage { get; init;}
+   public required Current Current { get; init;}
    
+   public Power Power => Current * Voltage;
+   
+   public static DcPhase operator |(DcPhase left, DcPhase right) => OpParallel(left, right);
+   private static readonly Func<DcPhase, DcPhase, DcPhase> OpParallel = "|".CreateBinaryOpForProps<DcPhase>();
+
+ 
 }
\ No newline at end of file
diff --git a/csharp/Lib/Units/Composite/IPhase.cs b/csharp/Lib/Units/Composite/IPhase.cs
new file mode 100644
index 000000000..b0ccfee66
--- /dev/null
+++ b/csharp/Lib/Units/Composite/IPhase.cs
@@ -0,0 +1,11 @@
+using System.Diagnostics.CodeAnalysis;
+
+namespace InnovEnergy.Lib.Units.Composite;
+
+[SuppressMessage("ReSharper", "MemberCanBeProtected.Global")]
+
+public interface IPhase
+{
+    public Voltage Voltage { get; }
+    public Current Current { get; }
+}
\ No newline at end of file
diff --git a/csharp/Lib/Units/Composite/Phase.cs b/csharp/Lib/Units/Composite/Phase.cs
deleted file mode 100644
index 45a3ef86d..000000000
--- a/csharp/Lib/Units/Composite/Phase.cs
+++ /dev/null
@@ -1,7 +0,0 @@
-namespace InnovEnergy.Lib.Units.Composite;
-
-public abstract record Phase
-(
-    Voltage Voltage, 
-    Current Current
-);
\ No newline at end of file
diff --git a/csharp/Lib/Units/Current.generated.cs b/csharp/Lib/Units/Current.generated.cs
index cda7eeadf..93e9bdbf7 100644
--- a/csharp/Lib/Units/Current.generated.cs
+++ b/csharp/Lib/Units/Current.generated.cs
@@ -18,25 +18,24 @@ public readonly partial struct Current
     public static T operator *(T t, Decimal scalar) => new T(scalar * t.Value);
     public static T operator /(T t, Decimal scalar) => new T(t.Value / scalar);
     
-    // addition
+    // parallel
     
     #if Sum
     
-    public static T operator +(T left, T right) => new T(left.Value + right.Value);
-    public static T operator -(T left, T right) => new T(left.Value - right.Value);
+    public static T operator |(T left, T right) => new T(left.Value + right.Value);
     public static T operator -(T t)             => new T(-t.Value);
     
     #elif Mean
     
-    public static T operator +(T left, T right) => new T((left.Value + right.Value)/2m);
+    public static T operator |(T left, T right) => new T((left.Value + right.Value)/2m);
     
     #elif Equal
     
-    public static T operator +(T left, T right)
+    public static T operator |(T left, T right)
     {
         var d = Max(Abs(left.Value), Abs(right.Value));
 
-        if (d != 0m)
+        if (d == 0m)
             return new T(0m);
 
         var relativeError = Abs(left.Value - right.Value) / d;
diff --git a/csharp/Lib/Units/Frequency.generated.cs b/csharp/Lib/Units/Frequency.generated.cs
index 015d67536..9618c18bc 100644
--- a/csharp/Lib/Units/Frequency.generated.cs
+++ b/csharp/Lib/Units/Frequency.generated.cs
@@ -18,25 +18,24 @@ public readonly partial struct Frequency
     public static T operator *(T t, Decimal scalar) => new T(scalar * t.Value);
     public static T operator /(T t, Decimal scalar) => new T(t.Value / scalar);
     
-    // addition
+    // parallel
     
     #if Sum
     
-    public static T operator +(T left, T right) => new T(left.Value + right.Value);
-    public static T operator -(T left, T right) => new T(left.Value - right.Value);
+    public static T operator |(T left, T right) => new T(left.Value + right.Value);
     public static T operator -(T t)             => new T(-t.Value);
     
     #elif Mean
     
-    public static T operator +(T left, T right) => new T((left.Value + right.Value)/2m);
+    public static T operator |(T left, T right) => new T((left.Value + right.Value)/2m);
     
     #elif Equal
     
-    public static T operator +(T left, T right)
+    public static T operator |(T left, T right)
     {
         var d = Max(Abs(left.Value), Abs(right.Value));
 
-        if (d != 0m)
+        if (d == 0m)
             return new T(0m);
 
         var relativeError = Abs(left.Value - right.Value) / d;
diff --git a/csharp/Lib/Units/Generator/Template.txt b/csharp/Lib/Units/Generator/Template.txt
index c656f51df..c78a3fcc6 100644
--- a/csharp/Lib/Units/Generator/Template.txt
+++ b/csharp/Lib/Units/Generator/Template.txt
@@ -18,25 +18,24 @@ public readonly partial struct Template
     public static T operator *(T t, Decimal scalar) => new T(scalar * t.Value);
     public static T operator /(T t, Decimal scalar) => new T(t.Value / scalar);
     
-    // addition
+    // parallel
     
     #if Sum
     
-    public static T operator +(T left, T right) => new T(left.Value + right.Value);
-    public static T operator -(T left, T right) => new T(left.Value - right.Value);
+    public static T operator |(T left, T right) => new T(left.Value + right.Value);
     public static T operator -(T t)             => new T(-t.Value);
     
     #elif Mean
     
-    public static T operator +(T left, T right) => new T((left.Value + right.Value)/2m);
+    public static T operator |(T left, T right) => new T((left.Value + right.Value)/2m);
     
     #elif Equal
     
-    public static T operator +(T left, T right)
+    public static T operator |(T left, T right)
     {
         var d = Max(Abs(left.Value), Abs(right.Value));
 
-        if (d != 0m)
+        if (d == 0m)
             return new T(0m);
 
         var relativeError = Abs(left.Value - right.Value) / d;
diff --git a/csharp/Lib/Units/Power.generated.cs b/csharp/Lib/Units/Power.generated.cs
index c26ad26fd..5ccca90ef 100644
--- a/csharp/Lib/Units/Power.generated.cs
+++ b/csharp/Lib/Units/Power.generated.cs
@@ -18,25 +18,24 @@ public readonly partial struct Power
     public static T operator *(T t, Decimal scalar) => new T(scalar * t.Value);
     public static T operator /(T t, Decimal scalar) => new T(t.Value / scalar);
     
-    // addition
+    // parallel
     
     #if Sum
     
-    public static T operator +(T left, T right) => new T(left.Value + right.Value);
-    public static T operator -(T left, T right) => new T(left.Value - right.Value);
+    public static T operator |(T left, T right) => new T(left.Value + right.Value);
     public static T operator -(T t)             => new T(-t.Value);
     
     #elif Mean
     
-    public static T operator +(T left, T right) => new T((left.Value + right.Value)/2m);
+    public static T operator |(T left, T right) => new T((left.Value + right.Value)/2m);
     
     #elif Equal
     
-    public static T operator +(T left, T right)
+    public static T operator |(T left, T right)
     {
         var d = Max(Abs(left.Value), Abs(right.Value));
 
-        if (d != 0m)
+        if (d == 0m)
             return new T(0m);
 
         var relativeError = Abs(left.Value - right.Value) / d;
diff --git a/csharp/Lib/Units/ReactivePower.generated.cs b/csharp/Lib/Units/ReactivePower.generated.cs
index 9b8def505..f438dd865 100644
--- a/csharp/Lib/Units/ReactivePower.generated.cs
+++ b/csharp/Lib/Units/ReactivePower.generated.cs
@@ -18,25 +18,24 @@ public readonly partial struct ReactivePower
     public static T operator *(T t, Decimal scalar) => new T(scalar * t.Value);
     public static T operator /(T t, Decimal scalar) => new T(t.Value / scalar);
     
-    // addition
+    // parallel
     
     #if Sum
     
-    public static T operator +(T left, T right) => new T(left.Value + right.Value);
-    public static T operator -(T left, T right) => new T(left.Value - right.Value);
+    public static T operator |(T left, T right) => new T(left.Value + right.Value);
     public static T operator -(T t)             => new T(-t.Value);
     
     #elif Mean
     
-    public static T operator +(T left, T right) => new T((left.Value + right.Value)/2m);
+    public static T operator |(T left, T right) => new T((left.Value + right.Value)/2m);
     
     #elif Equal
     
-    public static T operator +(T left, T right)
+    public static T operator |(T left, T right)
     {
         var d = Max(Abs(left.Value), Abs(right.Value));
 
-        if (d != 0m)
+        if (d == 0m)
             return new T(0m);
 
         var relativeError = Abs(left.Value - right.Value) / d;
diff --git a/csharp/Lib/Units/Resistance.cs b/csharp/Lib/Units/Resistance.cs
index ce426e229..ab0bc7bbe 100644
--- a/csharp/Lib/Units/Resistance.cs
+++ b/csharp/Lib/Units/Resistance.cs
@@ -2,6 +2,9 @@ using InnovEnergy.Lib.Units.Generator;
 
 namespace InnovEnergy.Lib.Units;
 
+
+// TODO: op parallel is wrong
+
 [Sum]
 public readonly partial struct Resistance
 {
diff --git a/csharp/Lib/Units/Resistance.generated.cs b/csharp/Lib/Units/Resistance.generated.cs
index 5be7685b6..134384467 100644
--- a/csharp/Lib/Units/Resistance.generated.cs
+++ b/csharp/Lib/Units/Resistance.generated.cs
@@ -18,25 +18,24 @@ public readonly partial struct Resistance
     public static T operator *(T t, Decimal scalar) => new T(scalar * t.Value);
     public static T operator /(T t, Decimal scalar) => new T(t.Value / scalar);
     
-    // addition
+    // parallel
     
     #if Sum
     
-    public static T operator +(T left, T right) => new T(left.Value + right.Value);
-    public static T operator -(T left, T right) => new T(left.Value - right.Value);
+    public static T operator |(T left, T right) => new T(left.Value + right.Value);
     public static T operator -(T t)             => new T(-t.Value);
     
     #elif Mean
     
-    public static T operator +(T left, T right) => new T((left.Value + right.Value)/2m);
+    public static T operator |(T left, T right) => new T((left.Value + right.Value)/2m);
     
     #elif Equal
     
-    public static T operator +(T left, T right)
+    public static T operator |(T left, T right)
     {
         var d = Max(Abs(left.Value), Abs(right.Value));
 
-        if (d != 0m)
+        if (d == 0m)
             return new T(0m);
 
         var relativeError = Abs(left.Value - right.Value) / d;
diff --git a/csharp/Lib/Units/State.cs b/csharp/Lib/Units/State.cs
index 752a5751d..af96735e0 100644
--- a/csharp/Lib/Units/State.cs
+++ b/csharp/Lib/Units/State.cs
@@ -14,5 +14,5 @@ public readonly struct State
     public static implicit operator State(Enum e)   => new State(e);
     public static implicit operator State(String s) => new State(s);
     
-    public static State operator +(State left, State right) => new State(left, right);
+    public static State operator |(State left, State right) => new State(left, right);
 }
\ No newline at end of file
diff --git a/csharp/Lib/Units/Temperature.cs b/csharp/Lib/Units/Temperature.cs
index dc2d7e5ad..57e2406a3 100644
--- a/csharp/Lib/Units/Temperature.cs
+++ b/csharp/Lib/Units/Temperature.cs
@@ -11,6 +11,5 @@ public readonly partial struct Temperature
     public static String Symbol => "T";
     
     public Temperature(Decimal value) => Value = value;
-
     
 }
\ No newline at end of file
diff --git a/csharp/Lib/Units/Temperature.generated.cs b/csharp/Lib/Units/Temperature.generated.cs
index edc3fdbfa..cc173ee61 100644
--- a/csharp/Lib/Units/Temperature.generated.cs
+++ b/csharp/Lib/Units/Temperature.generated.cs
@@ -18,25 +18,24 @@ public readonly partial struct Temperature
     public static T operator *(T t, Decimal scalar) => new T(scalar * t.Value);
     public static T operator /(T t, Decimal scalar) => new T(t.Value / scalar);
     
-    // addition
+    // parallel
     
     #if Sum
     
-    public static T operator +(T left, T right) => new T(left.Value + right.Value);
-    public static T operator -(T left, T right) => new T(left.Value - right.Value);
+    public static T operator |(T left, T right) => new T(left.Value + right.Value);
     public static T operator -(T t)             => new T(-t.Value);
     
     #elif Mean
     
-    public static T operator +(T left, T right) => new T((left.Value + right.Value)/2m);
+    public static T operator |(T left, T right) => new T((left.Value + right.Value)/2m);
     
     #elif Equal
     
-    public static T operator +(T left, T right)
+    public static T operator |(T left, T right)
     {
         var d = Max(Abs(left.Value), Abs(right.Value));
 
-        if (d != 0m)
+        if (d == 0m)
             return new T(0m);
 
         var relativeError = Abs(left.Value - right.Value) / d;
diff --git a/csharp/Lib/Units/Units.cs b/csharp/Lib/Units/Units.cs
index de1b246ad..98bc153e8 100644
--- a/csharp/Lib/Units/Units.cs
+++ b/csharp/Lib/Units/Units.cs
@@ -5,6 +5,8 @@ namespace InnovEnergy.Lib.Units;
 
 public static class Units
 {
+    public const Decimal MaxRelativeError = 0.05m; // 5%
+    
     public static Current       A      (this Decimal value) => new Current(value);
     public static Voltage       V      (this Decimal value) => new Voltage(value);
     public static Power         W      (this Decimal value) => new Power(value);
diff --git a/csharp/Lib/Units/Voltage.generated.cs b/csharp/Lib/Units/Voltage.generated.cs
index 07dc88d06..cdb63dcda 100644
--- a/csharp/Lib/Units/Voltage.generated.cs
+++ b/csharp/Lib/Units/Voltage.generated.cs
@@ -18,25 +18,24 @@ public readonly partial struct Voltage
     public static T operator *(T t, Decimal scalar) => new T(scalar * t.Value);
     public static T operator /(T t, Decimal scalar) => new T(t.Value / scalar);
     
-    // addition
+    // parallel
     
     #if Sum
     
-    public static T operator +(T left, T right) => new T(left.Value + right.Value);
-    public static T operator -(T left, T right) => new T(left.Value - right.Value);
+    public static T operator |(T left, T right) => new T(left.Value + right.Value);
     public static T operator -(T t)             => new T(-t.Value);
     
     #elif Mean
     
-    public static T operator +(T left, T right) => new T((left.Value + right.Value)/2m);
+    public static T operator |(T left, T right) => new T((left.Value + right.Value)/2m);
     
     #elif Equal
     
-    public static T operator +(T left, T right)
+    public static T operator |(T left, T right)
     {
         var d = Max(Abs(left.Value), Abs(right.Value));
 
-        if (d != 0m)
+        if (d == 0m)
             return new T(0m);
 
         var relativeError = Abs(left.Value - right.Value) / d;