  Consider a function where its entries are distributed among many parties.
Suppose each party is allowed to transmit only a limited amount of information
to a net. One can use a classical protocol to guess the value of the global
function. Is there a quantum protocol improving the results of all classical
protocols? Brukner et. al. showed the deep connection between such problems and
the theory of Bell's inequalities. Here we generalize the theory to trits.
There the best classical protocol fails whereas the quantum protocol yields the
correct answer.
