Linearisability is a central notion for verifying concurrent libraries: a given library is proven safe if its operational history can be rearranged into a new sequential one which, in addition, satisfies a given specification. Linearisability has been examined for libraries in which method arguments and method results are of ground type, including libraries parameterised with such methods. In this talk we extend linearisability to the general higher-order setting: methods can be passed as arguments and returned as values. A library may also depend on abstract methods of any order. This generalised notion, along with its encapsulated variant, can be shown to be sound using techniques from operational game semantics.

This is joint work with Andrzej Murawski.