3 papers
math.DG2026
Invariantised Euler-Lagrange equations and conserved quantities for nonconservative Herglotz variational problems
Tânia M. N. Gonçalves, Delfim F. M. Torres, Gastão S. F. Frederico
In this paper the structures of the generalised Euler-Lagrange equations and their associated conserved quantities are derived for one-dimensional Herglotz variational problems of…
math.OC2025
Fractional differential equations of a reaction-diffusion SIR model involving the Caputo-fractional time-derivative and a nonlinear diffusion operator
Achraf Zinihi, Moulay Rchid Sidi Ammi, Delfim F. M. Torres
The main aim of this study is to analyze a fractional parabolic SIR epidemic model of a reaction-diffusion, by using the nonlocal Caputo fractional time-fractional derivative and e…
math.OC2024
The Duality Theory of Fractional Calculus and a New Fractional Calculus of Variations Involving Left Operators Only
Delfim F. M. Torres
Through duality it is possible to transform left fractional operators into right fractional operators and vice versa. In contrast to existing literature, we establish integration b…