 
Summary: Distributed Computing manuscript No.
(will be inserted by the editor)
Dana Angluin · James Aspnes · Zoše Diamadi · Michael J. Fischer · RenŽe Peralta
Computation in Networks of Passively Mobile FiniteState Sensors
October 17, 2005
Abstract The computational power of networks of small
resourcelimited mobile agents is explored. Two new models
of computation based on pairwise interactions of finitestate
agents in populations of finite but unbounded size are de
fined. With a fairness condition on interactions, the concept
of stable computation of a function or predicate is defined.
Protocols are given that stably compute any predicate in the
class definable by formulas of Presburger arithmetic, which
includes Boolean combinations of thresholdk, majority, and
equivalence modulo m. All stably computable predicates are
shown to be in NL. Assuming uniform random sampling of
interacting pairs yields the model of conjugating automata.
Any counter machine with O(1) counters of capacity O(n)
can be simulated with high probability by a conjugating au
tomaton in a population of size n. All predicates computable
