  Partial mutual exclusion is the drinking philosophers problem for complete
graphs. It is the problem that a process may enter a critical section CS of its
code only when some finite set nbh of other processes are not in their critical
sections. For each execution of CS, the set nbh can be given by the
environment. We present a starvation free solution of this problem in a setting
with infinitely many processes, each with finite memory, that communicate by
asynchronous messages. The solution has the property of first-come
first-served, in so far as this can be guaranteed by asynchronous messages. For
every execution of CS and every process in nbh, between three and six messages
are needed. The correctness of the solution is argued with invariants and
temporal logic. It has been verified with the proof assistant PVS.
