Analytical and approximate monotone solutions of the mixed order fractional nabla operators subject to bounded conditions

In this study, the sequential operator of mixed order is analysed on the domain (μ2,μ1)∈(0,1)×(0,1) with 1<μ2+μ1<2. Then, the positivity of the nabla operator is obtained analytically on a finite time scale under some conditions. As a consequence, our analytical results are introduced on a set, named Em,ζ, on which the monotonicity analysis is obtained. Due to the complicatedness of the set Em,ζ several numerical simulations so are applied to estimate the structure of this set and they are provided by means of heat maps.