In this paper, we are interested in studying the spread of infectious disease using a fractional-order model with Caputo's fractional derivative operator. The considered model includes an infectious disease that includes two types of infected class, the first shows the presence of symptoms (symptomatic infected persons), and the second class does not show any symptoms (asymptomatic infected persons). Further, we considered a nonlinear incidence function, where it is obtained that the investigated fractional system shows some important results. In fact, different types of bifurcation are obtained, as saddle-node bifurcation, transcritical bifurcation, Hopf bifurcation, where it is discussed in detail through the research. For the numerical part, a proper numerical scheme is used for the graphical representation of the solutions. The mathematical findings are checked numerically.

In this article we explore the existence, uniqueness, and stability for a coupled system of sequential fractional integrodifferential equations involving $\psi$–Hilfer fractional derivative with multi–point boundary conditions. For the uniqueness result we use Banach fixed point theorem, and the Leray–Schauder alternative to obtain the existence result. Further, we investigate various kinds of stability such as Hyers–Ulam stability. Examples are provided to verify our results.

In this article, we introduced the concept of neutrosophic metric-like spaces and obtained some fixed point results in the sense of neutrosophic metric-like spaces. Our results are improvements of recent results in the existing literature. For the validity of these results some non-trivial examples are imparted.

This paper aims to investigate a new type of derivations in a fuzzy Banach algebra. Moreover, by using the fixed point method, we obtain some stability results of the hom-der in fuzzy Banach algebras associated with the functional equation

$$f(x+ky)=f(x)+kf(y)$$

where $k$ is a fixed positive integer greater than $1$.