 
Summary: PHASECONVEX ARCS
IN ROOT SPACE AND
THEIR APPLICATION TO
ROBUST SPR PROBLEMS
F. P’erez # , C. Abdallah +
* ETSI Telecomunicacion, Universidad de Vigo, 36200VIGO, SPAIN
+ EECE Dept., University of New Mexico, Albuquerque, NM 87131, USA.
ABSTRACT
This paper considers the problem of identifying regions
in the complexplane, such that the phase of polynomials
having roots in those regions, is bounded by that of a few
extreme polynomials. Applications of the results are also
described.
1 Introduction
This short paper considers the problem of identifying re
gions in the complexplane, such that the phase of poly
nomials having roots in those regions, is bounded by that
of a few extreme polynomials. More specifically, given a
family of polynomials P (z 1 )
P (z 1 ) = {p(z 1 ); p(z 1 i ) = 0 # z i
