Pareto frontier or Pareto set. In multi-objective optimization, when the
different objectives are contradictory, an optimal solution is said Pareto
optimal when it is not possible to improve an objective without degrading the
others. A Pareto optimal solution can then be seen as an optimal trade-off
between the objectives. The set of all Pareto optimal solutions is called the
Pareto front as it usually graphically forms a distinct front of points.
Solutions which do not lay on the Pareto front are called Pareto dominated
solutions. The figure shows a typical convex Pareto front obtained when
minimizing two objectives concurrently.