In the application of the problem-solution approach for the assessment of inventive step, the person skilled in the art within the meaning of Article 56 EPC enters the stage only when the objective technical problem has been formulated in view of the selected "closest prior art". Only then can the notional skilled person's relevant technical field and its extent be appropriately defined. Therefore, it cannot be the "skilled person " who selects the closest prior art in the first step of the problem-solution approach. Rather, this selection is to be made by the relevant deciding body, on the basis of the established criteria, in order to avoid any hindsight analysis (see point 2.1.4 of the Reasons).