Parallel solutions for preemptive makespan scheduling on two identical machines

We consider online preemptive scheduling of jobs arriving one by one, to be assigned two identical machines, with the goal makespan minimization. study effect selecting best solution out independent solutions constructed in parallel an fashion. Two cases are analyzed, where case is purely online, and other presented sorted non-increasing sizes. show that using rather than improves performance significantly, but optimal cannot obtained for any constant number parallel. Our algorithms have possible competitive ratios each classes.