Problem Session at ALCOM-91

We present the problems posed at the special session of the International Workshop on Algebraic Combinatorics (ALCOM-91), held in Vladimir, Russia, on 6-17 August 1991. The problems are arranged into 4 sections by their subjects: association schemes, geometries, graphs and the theory of computation. To the problems posed at the session we adjoin a problem by L. Babai that is closely related to the problem formulated by L. Pyber. tion about the dimension of the universal natural representation of the tilde geometry associated with Heldʹs group was posed at the session. Soon after the workshop the question was answered by one of the participants, namely B. D. McKay, who determined by computer the GF(2)-corank of a system of 437,325 equations over 29,155 variables. The dimension of the universal representation, equal to this corank, turned out to be 52. A 51-dimensional representation of the geometry was known previously [10].