C# 4.0 allows to declare variance compatibility for delegates and interfaces. This means, for instance, that one can assign an IEnumerable<Cat> to an IEnumerable<Animal>.  The term variance compatibility, in this context, defines the kind of assignment compatibility between two closed generic types, which exists when the parameters of those types are derived from each other (or are themselves variant to each other). In other words: Given two types T1<P1> and T2<P2>,  variance defines how T1 is assignment c[...]

The library System.Numerics.dll, who was introduced in .Net 4.0, contains a System.Numerics.BigInteger structure. BigInteger represents a whole number of arbitrary size (or precision). Before .Net 4.0, the largest number that could be represented "out of the box" was System.Double.MaxValue. Written in decimal notation, this would be a whole number with 309 digits (more than 179 thousand centillion). However, using Double for whole number calculations is error-prone. [...]

The library System.Numerics.dll, who was introduced in .Net 4.0, contains a System.Numerics.BigInteger structure. BigInteger represents a whole number of arbitrary size (or precision). Before .Net 4.0, the largest number that could be represented "out of the box" was System.Double.MaxValue. Written in decimal notation, this would be a whole number with 309 digits (more than 179 thousand centillion). However, using Double for whole number calculations is error-prone. [...]

In F#, class constructors can be declared in several different ways. To declare a non-static class, one usually defines a primary constructor, plus zero or more additional constructors. To declare a static class, one usually defines a module. Using a Primary Constructor In F#, it is possible to create a thread-safe singleton with just three lines of code: /// A public thread-safe singleton class in F#, /// using a private primary constructor. type Singleton private() = static let instance = Singleton()[...]

In F#, class constructors can be declared in several different ways. To declare a non-static class, one usually defines a primary constructor, plus zero or more additional constructors. To declare a static class, one usually defines a module. Using a Primary Constructor In F#, it is possible to create a thread-safe singleton with just three lines of code: /// A public thread-safe singleton class in F#, /// using a private primary constructor. type Singleton private() = static let instance = Singleton()[...]