diff --git a/src/Numerics/Complex32.cs b/src/Numerics/Complex32.cs
index 26d841e5..d2f8894f 100644
--- a/src/Numerics/Complex32.cs
+++ b/src/Numerics/Complex32.cs
@@ -70,7 +70,7 @@ namespace MathNet.Numerics
     [Serializable]
     [StructLayout(LayoutKind.Sequential)]
     [DataContract(Namespace = "urn:MathNet/Numerics")]
-    public struct Complex32 : IFormattable, IEquatable<Complex32>
+    public readonly struct Complex32 : IFormattable, IEquatable<Complex32>
     {
         /// <summary>
         /// The real component of the complex number.
diff --git a/src/Numerics/Control.cs b/src/Numerics/Control.cs
index 6cc07eb4..3028af03 100644
--- a/src/Numerics/Control.cs
+++ b/src/Numerics/Control.cs
@@ -241,7 +241,7 @@ namespace MathNet.Numerics
         /// </summary>
         public static string NativeProviderPath
         {
-            get { return _nativeProviderHintPath; }
+            get => _nativeProviderHintPath;
             set
             {
                 _nativeProviderHintPath = value;
@@ -257,7 +257,7 @@ namespace MathNet.Numerics
         /// <remarks>Default to the number of processor cores, must be between 1 and 1024 (inclusive).</remarks>
         public static int MaxDegreeOfParallelism
         {
-            get { return _maxDegreeOfParallelism; }
+            get => _maxDegreeOfParallelism;
             set
             {
                 _maxDegreeOfParallelism = Math.Max(1, Math.Min(1024, value));
@@ -280,8 +280,8 @@ namespace MathNet.Numerics
         /// <value>The order. Default 64, must be at least 3.</value>
         internal static int ParallelizeOrder
         {
-            get { return _parallelizeOrder; }
-            set { _parallelizeOrder = Math.Max(3, value); }
+            get => _parallelizeOrder;
+            set => _parallelizeOrder = Math.Max(3, value);
         }
 
         /// <summary>
@@ -291,8 +291,8 @@ namespace MathNet.Numerics
         /// <value>Number of elements. Default 300, must be at least 3.</value>
         internal static int ParallelizeElements
         {
-            get { return _parallelizeElements; }
-            set { _parallelizeElements = Math.Max(3, value); }
+            get => _parallelizeElements;
+            set => _parallelizeElements = Math.Max(3, value);
         }
 
         public static string Describe()
diff --git a/src/Numerics/Optimization/QuadraticGradientProjectionSearch.cs b/src/Numerics/Optimization/QuadraticGradientProjectionSearch.cs
index 03a5bb8c..9e203697 100644
--- a/src/Numerics/Optimization/QuadraticGradientProjectionSearch.cs
+++ b/src/Numerics/Optimization/QuadraticGradientProjectionSearch.cs
@@ -112,7 +112,7 @@ namespace MathNet.Numerics.Optimization
             }
         }
 
-        public struct GradientProjectionResult
+        public readonly struct GradientProjectionResult
         {
             public GradientProjectionResult(Vector<double> cauchyPoint, int fixedCount, List<bool> isFixed)
             {