A New Generalization of Tychonoff and Darbo Theorems and Solving a Class of Systems of Fredholm Integral Equations on Unbounded Domains

In this paper, a new extension of Tychonoff and Darbo theorems via the family of measures of noncompactness (FMN) is given. Moreover, several results on coupled fixed points and multi-variable condensing operators in a Fréchet space are presented. To support main results, the existence of solutions for a class of systems of n -variable Fredholm integral equations on unbounded domains is also discussed, which can include some previous systems in the existing literature.