  Requirements Engineering (RE) focuses on eliciting, modelling, and analyzing
the requirements and environment of a system-to-be in order to design its
specification. The design of the specification, usually called the Requirements
Problem (RP), is a complex problem solving task, as it involves, for each new
system-to-be, the discovery and exploration of, and decision making in, new and
ill-defined problem and solution spaces. The default RP in RE is to design a
specification of the system-to-be which (i) is consistent with given
requirements and conditions of its environment, and (ii) together with
environment conditions satisfies requirements. This paper (i) shows that the
Requirements Problem for Adaptive Systems (RPAS) is different from, and is not
a subclass of the default RP, (ii) gives a formal definition of RPAS, and (iii)
discusses implications for future research.
