Investigating the Convergence of Sigmoid-Based Fuzzy General Grey Cognitive Maps
Xudong Gao, Xiaoguang Gao, Jia Rong, Xiaolei Li, Ni Li, Yifeng Niu, Jun Chen
TL;DR
The paper addresses convergence analysis for sigmoid-based FGGCMs, a grey-number–aware extension of fuzzy cognitive maps. Using Banach and Browder-Gohde-Kirk fixed-point frameworks, it derives sufficient conditions for both kernel and greyness convergence to fixed points when using sigmoid activations with general grey numbers. Key contributions include unifying FCM, FGCM, and FGGCM under a common theoretical framework, enabling convergence guarantees even with complex GGNs and mixed-sign weights, and demonstrating practical validation on Web Experience scenarios. The findings enhance the reliability and applicability of FGGCMs in control, prediction, and decision-support tasks under uncertainty, while outlining future work on other activations and more efficient learning algorithms.
Abstract
The Fuzzy General Grey Cognitive Map (FGGCM) and Fuzzy Grey Cognitive Map (FGCM) extend the Fuzzy Cognitive Map (FCM) by integrating uncertainty from multiple interval data or fuzzy numbers. Despite extensive studies on the convergence of FCM and FGCM, the convergence behavior of FGGCM under sigmoid activation functions remains underexplored. This paper addresses this gap by deriving sufficient conditions for the convergence of FGGCM to a unique fixed point. Using the Banach and Browder-Gohde-Kirk fixed point theorems, and Cauchy-Schwarz inequality, the study establishes conditions for the kernels and greyness of FGGCM to converge to unique fixed points. A Web Experience FCM is adapted to design an FGGCM with weights modified to GGN. Comparisons with existing FCM and FGCM convergence theorems confirm that they are special cases of the theorems proposed here. The conclusions support the application of FGGCM in domains such as control, prediction, and decision support systems.
