In this paper, the existence, uniqueness and stability of solutions to a boundary value problem of nonlinear FDEs of variable order are established. To do this, we first investigate some aspects of variable order operators of Hadamard type. Then, with the help of the generalized intervals and piecewise constant functions, we convert the variable order Hadamard FBVP to an equivalent standard Hadamard BVP of the fractional constant order. Further, two fixed point theorems due to Schauder and Banach are used and, finally, the Ulam–Hyers–Rassias stability of the given variable order Hadamard FBVP is examined. These results are supported with the aid of a comprehensive example.

A boundary value problem for Hadamard fractional differential equations of variable order is studied. Note the symmetry of a transformation of a system of differential equations is connected with the locally solvability which is the same as the existence of solutions. It leads to the necessity of obtaining existence criteria for a boundary value problem for Hadamard fractional differential equations of variable order. Also, the stability in the sense of Ulam–Hyers–Rassias is investigated. The results are obtained based on the Kuratowski measure of noncompactness. An example illustrates the validity of the observed results.

The aim of this research paper is to establish sufficient conditions for the nonexistence of global solutions for the following nonlinear fractional differential equation D?0|tu + (??)?/2|u|m?1u + a(x)??|u|q?1u = h(x, t)|u|p, (t,x) ? Q, u(0, x) = u0(x), x ? RN where (??)?/2, 0 < ? < 2 is the fractional power of ??, and D?0|t, (0 < ? < 1) denotes the time-derivative of arbitrary ? ? (0; 1) in the sense of Caputo. The results are shown by the use of test function theory and extended to systems of the same type.

The aim of the present study is to find the exact solutions for three generalized nonlinear time-fractional evolution equations, Kaup-Kupershmidt equation, Burgers-Fisher equation and, Shallow Water Wave equation. By using the (G’/G)-expansion method and depending on second order linear ODE as well as the complex transformation, three kinds of solutions (hyperbolic, trigonometric, and rational) are obtained. With the help of Mathematica software package, difficult algebraic systems are solved and surfaces of some particular solutions of the equations under study are plotted.