Title
Limit Set Dichotomy and Multistability for a Class of Cooperative Neural Networks With Delays.
Abstract
Recent papers have pointed out the interest to study convergence in the presence of multiple equilibrium points (EPs) (multistability) for neural networks (NNs) with nonsymmetric cooperative (nonnegative) interconnections and neuron activations modeled by piecewise linear (PL) functions. One basic difficulty is that the semiflows generated by such NNs are monotone but, due to the horizontal segments in the PL functions, are not eventually strongly monotone (ESM). This notwithstanding, it has been shown that there are subclasses of irreducible interconnection matrices for which the semiflows, although they are not ESM, enjoy convergence properties similar to those of ESM semiflows. The results obtained so far concern the case of cooperative NNs without delays. The goal of this paper is to extend some of the existing results to the relevant case of NNs with delays. More specifically, this paper considers a class of NNs with PL neuron activations, concentrated delays, and a nonsymmetric cooperative interconnection matrix A and delay interconnection matrix A(tau). The main result is that when A + A(tau) satisfies a full interconnection condition, then the generated semiflows, which are monotone but not ESM, satisfy a limit set dichotomy analogous to that valid for ESM semiflows. It follows that there is an open and dense set of initial conditions, in the state space of continuous functions on a compact interval, for which the solutions converge toward an EP. The result holds in the general case where the NNs possess multiple EPs, i.e., is a result on multistability, and is valid for any constant value of the delays.
Year
DOI
Venue
2012
10.1109/TNNLS.2012.2205703
IEEE Trans. Neural Netw. Learning Syst.
Keywords
Field
DocType
Cooperative dynamical systems, delayed neural networks, limit set dichotomy, monotone semiflows, multistability
Convergence (routing),Computer science,Equilibrium point,Artificial intelligence,Multistability,Monotone polygon,Discrete mathematics,Topology,Continuous function,Pattern recognition,Strongly monotone,State space,Limit set
Journal
Volume
Issue
ISSN
23
9
2162-237X
Citations 
PageRank 
References 
17
0.64
11
Authors
4
Name
Order
Citations
PageRank
Mauro Di Marco120518.38
Mauro Forti239836.80
Massimo Grazzini313111.01
Luca Pancioni420717.58