fact: Definition lr_connected (c1 c2 : cell) : bool := existsb (fun v => existsb (fun v' => vert_edge_eqb v v') (cell_safe_exits_left c2)) (cell_safe_exits_right c1).
imports: mathcomp(all_ssreflect) ZArith QArith List String OrderedType OrderedTypeEx FMapAVL