The syntax `Nullable<T>` (displayed as `Nullable`1` in some contexts, like...

The syntax Nullable<T> (displayed as Nullable1` in some contexts, like type signatures or reflective introspection) pertains to the construction of nullable value types in .NET languages, such as C#. Specifically:

1. Nullable<T> is a generic structure that allows a value type (T) to either have a value of its own type or to be null.
2. Value types like int, double, and bool in .NET are inherently non-nullable, meaning they must always have a value. However, by wrapping them in a Nullable<T>, they can also represent a null value.
3. This is commonly used when it is meaningful for a value type to have no value (e.g., a database field that may contain a missing/empty value).

For example:

int? number = null; // Shorthand for Nullable<int>
if (number.HasValue)
{
    Console.WriteLine(number.Value);
}
else
{
    Console.WriteLine("number is null");
}

Here:

• int? is syntactic sugar for Nullable<int>.
• number.HasValue checks whether the nullable has a value.
• number.Value retrieves the underlying value if it exists.

In summary, Nullable<T> (or Nullable1` when represented in some internal or reflective contexts) adds the ability for value types to be null in C#.