Lattice Linearity in Assembling Myopic Robots on an Infinite Triangular Grid

In this paper, we study the problem of gathering distance-1 myopic robots on an infinite triangular grid. We show that the algorithm developed by Goswami et al. (SSS, 2022) is lattice linear. This implies that a distributed scheduler, assumed therein, is not required for this algorithm: it runs correctly in asynchrony. It also implies that the algorithm works correctly even if the robots are equipped with a unidirectional \textit{camera} to see the neighbouring robots (rather than an omnidirectional one, which would be required under a distributed scheduler). Due to lattice linearity, we can predetermine the point of gathering. We also show that this algorithm converges in $2n$ rounds, which is lower than that ($2.5(n+1)$ rounds) shown in Goswami et al.