The Attributed Pi-Calculus with Priorities

We present the attributed

π

− 

calculus

for modeling concurrent systems with interaction constraints depending on the values of attributes of processes. The

λ

-calculus serves as a constraint language underlying the

π

− 

calculus

. Interaction constraints subsume priorities, by which to express global aspects of populations. We present a non-deterministic and a stochastic semantics for the attributed

π

− 

calculus

. We show how to encode the

π

− 

calculus

with priorities and polyadic synchronization

π

− @ and thus dynamic compartments, as well as the stochastic

π

− 

calculus

with concurrent objects

spico

.

We illustrate the usefulness of the attributed

π

− 

calculus

for modeling biological systems at two particular examples: Euglena’s spatial movement in phototaxis, and cooperative protein binding in gene regulation of bacteriophage lambda. Furthermore, population-based model is supported beside individual-based modeling. A stochastic simulation algorithm for the attributed

π

− 

calculus

is derived from its stochastic semantics. We have implemented a simulator and present experimental results, that confirm the practical relevance of our approach.