Furthermore it had to be considered that an objective definition of the problem to be solved by the invention should normally start from the problem described in the contested patent. Only if examination showed that the problem disclosed had not been solved or if inappropriate prior art were used to define the problem, was it necessary to investigate which other problem objectively existed. The definition of artificial and technically unrealistic problems was to be avoided (see T 246/91, T 495/91, T 731/91, T 741/91, T 334/92, T 881/92, T 380/93, T 813/93, T 68/95, T 644/97, T 747/97 and T 946/00). This legal principle is also applicable to ex parte proceedings (T 881/92, T 882/92, T 884/92). In T 419/93 it was added that, when determining the problem, the statements relating thereto in the application should be examined for correctness with regard to the prior art and for their de facto relevance to the claimed features of the solution. Only if the problem described in the application did not meet prior art requirements and/or was not solved in accordance with the features of the invention, should it be adapted to the prior art and/or actual technical success. In this connection, T 800/91 emphasised that in any event the formulated problem should be one which the skilled person knowing only the prior art would wish to solve. It should not be tendentiously formulated in a way that unfairly directed development towards the claimed solution. In T 400/98, the technical problem set out in the patent at issue had to be reformulated because it had not been credibly solved.