Let G be a discrete group, let p
1,
and let Lp(G) denote the
Banach space
{Sg
Gagg | Sg
G| ag|p <
}. The following problem will
be studied: given
0
a
G and
0
b
Lp(G), is
a*b
0? We will
concentrate on the case G is a free abelian or
free group.