%T Types, Orthogonality and Genericity: Some Tools for Communicating Process Architectures
%A  Samson Abramsky
%E Peter H. Welch,  S. Stepney,  F.A.C Polack,  Frederick R. M. Barnes,  Alistair A. McEwan,  G. S. Stiles,  Jan F. Broenink,  Adam T. Sampson
%B Communicating Process Architectures 2008
%X We shall develop a simple and natural formalization of the
   idea
of <i>client\-server</i> architectures, and, based on
   this, define
a notion of <i>orthogonality</i> between
   clients and servers,
which embodies strong correctness
   properties, and exposes the rich
logical structure inherent
   in such systems. Then we generalize
from pure clients and
   servers to <i>components</i>, which provide
some services to
   the environment, and require others from it.
We identify the
   key notion of <i>composition</i> of such components,
in
   which some of the services required by one component are
   supplied
by another. This allows complex systems to be built
   from ultimately
simple components. We show that this has the
   logical form of the
<i>Cut rule</i>, a fundamental principle
   of logic, and that it
can be enriched with a suitable notion
   of <i>behavioural types</i>
based on orthogonality, in such
   a way that correctness properties
are preserved by
   composition. We also develop the basic ideas of
how logical
   constructions can be used to develop
   <i>structured
interfaces</i> for systems, with operations
   corresponding to
logical rules. Finally, we show how the
   setting can be enhanced,
and made more robust and
   expressive, by using <i>names</i> (as in
the &pi;\-calculus)
   to allow clients to bind dynamically to generic
instances of
   services.