Summary: Flow-sensitive Type Systems and the Ambient
Torben Amtoft 2
Department of Computing and Information Sciences, Kansas State University,
Manhattan KS 66506, USA
The Ambient Calculus was developed by Cardelli and Gordon as a formal frame-
work to study issues of mobility and migrant code. Numerous analyses have been
developed for numerous variants of that calculus. We take up the challenge of de-
veloping, in a type-based setting, a relatively precise "topology" analysis for the
original version of the calculus. To compensate for the lack of "co-capabilities" (an
otherwise increasingly popular extension), the analysis is flow-sensitive, with the
actions of processes being summarized by "behaviors".
A subject reduction property guarantees that for a well-typed process, the lo-
cation of any ambient is included in what is predicted by its type; additionally it
ensures that communicating subprocesses agree on their "topic of conversation".
Based on techniques borrowed from finite automata theory, type checking of type-
annotated processes is decidable.
For program analysis, several frameworks have been devised, as described in