(IN)COMPLETENESS IN SPECIFICATIONS

Completeness is usually listed as a desirable attribute of specifications; incompleteness, as a reason for the failure of software to satisfy its intended requirements. Unfortunately, these terms are rarely given anything but intuitive definitions, making it unclear how to achieve the former, or alternatively, avoid the latter. This article examines the notion of (in)completeness in specifications from a number of perspectives, and then introduces a pragmatic definition of incompleteness: a classification based on its potential sources. From this, it observes that completeness, though needed to properly, reason about, and capture the behaviour of, the system, is undesirable in some cases.