In T 314/99 the three different embodiments which were covered by claim 1 did not belong to the same single general inventive concept (Art. 82 EPC 1973). According to G 1/91 (OJ 1992, 253) lack of unity is not an issue in opposition (or opposition appeal) proceedings. In the case in point the board stated that the consequence of this conceptual lack of unity is that different aspects of the problem apply to the three embodiments and that where conceptual non-unity arises between different embodiments covered by a claim, this may necessitate the formulation of corresponding partial problems, the respective solutions of which must be assessed separately for inventive step. With respect to the requirements of Art. 56 EPC 1973 the inventiveness of the subject-matter of a claim must be denied as a whole in the event that only one of its embodiments is obvious.