"The alleged opinion that studies in seminars [in classes] are of the highest scientific nature, while exercises in solving problems are of the lowest [rank], is unfair. Mathematics to a considerable extent consists in solving problems, [and] together with proper discussion, [this] can be of the highest scientific nature while studies in ... seminars might be of the lowest [rank]."
Source: http://www.sciencedirect.com/science/article/pii/S0024379504000357
