On the Computational Power of Mobile Robots Under Sequential Schedulers

We consider distributed systems of autonomous, punctiform, mobile robots that operate in the Euclidean plane by executing an infinite sequence of Look-Compute-Move cycles. Robots are anonymous, indistinguishable, homogeneous, and disoriented. In literature, four base models have been proposed to study four different memory-communication settings: (oblivious and silent), (finite-state and silent), (oblivious and finite-communication), and (finite-state and finite-communication). In particular, the research has investigated how the computational power of these models is affected by considering three main classes of robot schedulers: FSYNCH (fully synchronous), SSYNCH (semi-synchronous), and ASYNCH (asynchronous). This paper focuses on a peculiar type of SSYNCH schedulers, the sequential ones, which activate only one robot at each round. We consider three subclasses: the general sequential scheduler (SEQ), the permutation scheduler (PERM), and the well-known round-robin (RROBIN). For each base model, we investigate how the robots’ computational power changes as the scheduler class varies, thus providing a first overview of the computational landscape of sequential schedulers.