A list is a basic Yacas container object. A list is written as e.g. {a, b, c} or {} (empty list). Individual elements of a list can be accessed using the [] operation. Lists can be concatenated, and individual elements can be removed or inserted. Lists are ubiquitous in Yacas. Most data structures in the standard library is based on lists. Lists are also used internally to represent Yacas expressions. For example, the expression Cos(x+1) is represented internally as a nested list