How do I create a new empty map (or set or sequence)?

Question

How do I create a new empty map (or set or sequence)?

Answer

An empty sequence is denoted by [], an empty set by {}, an empty multiset by multiset{}, and an empty map by map[]. The type of the empty collection is typically inferred from its subsequent use.

The various operations on values of these types are described in the reference manual section on Collection Types.