Silent Self-Stabilising Leader Election in Programmable Matter Systems with Holes

Abstract: Leader election is a fundamental problem in distributed computing, particularly within programmable matter systems, where coordination among simple computational entities is crucial for solving complex tasks. In these systems, particles (i.e., constant memory computational entities) operate in a regular triangular grid as described in the geometric Amoebot model. While leader election has been extensively studied in non self-stabilising settings, self-stabilising solutions remain more limited. In this work, we study the problem of self-stabilising leader election in connected (but not necessarily simply connected) configurations. We present the first self-stabilising algorithm for programmable matter that guarantees the election of a unique leader under an unfair scheduler, assuming particles share a common sense of direction. Our approach leverages particle movement, a capability not previously exploited in the self-stabilising context. We show that movement in conjunction with particles operating in a grid can overcome classical impossibility results for constant-memory systems established by Dolev et al.