Cournot oligopoly Gerasimov–Caputo fractional derivative HIV infection Hilbert space Hopf bifurcation NSFD SEIRS model age structure arbitration arguments asymptotics bic Book Industry Communication::G Reference, information & interdisciplinary subjects::GP Research & information: general bic Book Industry Communication::P Mathematics & science characteristics method compact difference scheme consumer-resource model convergence analysis convergence and stability degenerate evolution equation delay differential equation delay random differential equation delay systems difference scheme differential equation with delay dynamic consistency eclipse phase finite difference method fixed point theorem fractional convection diffusion-wave equations freight options growth rate dynamics