MPI-I-93-162

We prove that almost all Boolean function has a high $k$--party communication complexity. The 2--party case was settled by {\it Papadimitriou} and {\it Sipser}. Proving the $k$--party case needs a deeper investigation of the underlying structure of the $k$--cylinder--intersections; (the 2--cylinder--intersections are the rectangles). \noindent First we examine the basic properties of $k$--cylinder--intersections, then an upper estimation is given for their number, which facilitates to prove the lower--bound theorem for the $k$--party communication complexity of randomly chosen Boolean functions. In the last section we extend our results to the $\varepsilon$--distributional communication complexity of random functions.