Let A = {a(1),.a(2),...} subset of or equal to N and put A(n) = Sigma (ai l
ess than or equal ton) 1. We say that A is a P-set if no element ni divides
the sum of two larger elements. It is proved that for every P-set A with p
airwise co-prime elements the inequality A(n) < 2n(2/3) holds for infinitel
y many n <is an element of> N. (C) 2001 Academic Press.