20M30 20M35 5 16G 3 20M05 3 68Q70 3 05C25 2 08B15 2 20B10 2 20B30 2 20C99 2 20E99 2 20F10 2 20K99 2 20M10 2 20M18 2 20M19 2 20N99 2 Abelian digroups 2 Cayley graph 2 Rees matrix semigroup 2 Schreier graphs 2 \(0\)-semisimple matrix 2 actions and representations 2 automaton groups 2 automaton semigroups 2 completely regular 2 completely simple semigroups 2 defining relations 2 digraph 2 digroups 2