Unit-time open-shop scheduling problems with symmetric objective functions

The paper deals with the open??shop problems with unit??time operations and nonde??creasing symmetric objective functions depending on job completion times??. We construct two schedules??, one of them is optimal for any symmetric convex function??, the other is optimal for any symmetric concave function.?? Each of these two schedules is given by an analytically defined function which assigns to each operation the number of a unit-??time slot for its processing??.