Recent database research has given much attention to the specification
of ''flexible'' transactions that can be used in interoperable system
s. Starting from a quite different angle, Business Process Modelling h
as approached the area of communication modelling as well. The Languag
e/Action perspective describes business processes by means of speech a
cts and commitments. These can be formalized by means of extended deon
tic logic. We argue that this logic provides the right concepts for sp
ecifying flexible transactions. To impose a modular structure on the s
pecification, we make a distinction between the transaction level, the
task level, and the contract. Extended deontic logic also offers the
operators (communicative actions) by means of which one business proce
ss can be transformed into another. When these operators are provided
to the subjects, business processes need no longer be seen as fixed on
ce, but can become the subject of continuous negotiation and adaptatio
n. (C) 1997 Elsevier Science Ltd.