Analysis on Krasnoselskii’s fixed point theorem of fuzzy variable fractional differential equation for a novel coronavirus (COVID-19) model with singular operator

Abstract

The fuzzy variable fractional differential equations (FVFDEs) play a very important role in mathematical modeling of COVID-19. The scientists are studying and developing several aspects of these COVID-19 models. The existence and uniqueness of the solution, stability analysis are the most common and important study aspects. There is no study in the literature to establish the existence, uniqueness, and UH stability for fuzzy variable fractional (FVF) order COVID-19 models. Due to high demand of this study, we investigate results for the existence, uniqueness, and UH stability for the considered COVID-19 model based on FVFDEs using a fixed point theory approach with the singular operator. Additionally, discuss the maximal/minimal solution for the FVFDE of the COVID-19 model.