Analyses of network problems have yielded mathematically and practical
ly significant results. Naturally, it should be of substantial interes
t to extend such results to a general class of network problems where
the structure of any system can be represented by a directed bipartite
graph containing two types of vertices; the model for one of them is
nonlinear. This class of problems is frequently encountered in the des
ign of process systems for carrying out transformation of chemical or
material species through physical, chemical, or biological means. Gene
ral-purpose mathematical programming methods have failed so far to sol
ve large-scale network problems involved in the design of such systems
. This paper is intended to define this class of network problems, i.e
., the problems of process network synthesis, and to elucidate the uni
que features of these problems. (C) 1998 John Wiley & Sons, Inc.