STILL ANOTHER RANK DETERMINATION OF SET INTERSECTION MATRICES WITH ANAPPLICATION IN COMMUNICATION COMPLEXITY

The set-intersection function gives the cardinality of the intersectio n of two sets. In order to obtain a lower bound for the communication complexity of this function, the rank of the corresponding characteris tic function-value matrices was calculated in [1] and [2]. In this not e, the rank of these matrices is determined by another method of proof , which makes use of a factorization into a product of an upper and a lower triangular matrix.