We prove that any polynomial having all its roots ina closed half-plan
e, whose boundary contains the origin, has either one or two maximal p
oints, and only one if it has at least one root in the open half-plane
. This result concerns stable polynomials as well as polynomials havin
g only real roots, including real orthogonal polynomials. (C) 1998 Aca
demic Press.