This paper deals with the theory of codimension one bifurcations applied to a dynamical system derivedfrom applying Pontryagin 's maximum principIe to an optimal control problem for economic fisheries management. Changes in the number and/or the stability of stationary states as well as the appearance of closed orbits, are analyzed. Some necessCl.'Y and/or sufficient conditions are established ...

Due to the encouraging increase in their applications, control theory [Lefschetz, 1965] and [Narendra et al., 1973], design of electric circuits [Chua et al., 1990], neurobiology [FitzHugh, 1961] and [Nagumo et al., 1962] piecewise linear differential systems were studied early from the point of view of qualitative theory of ordinary differential equations [Andronov et al., 1966]. Nowadays, a l...

This is a review of strong coupling approaches to grasp the nature of the phase transition in finite temperature and density QCD. We commence with classics of the center symmetry and the Polyakov loop in pure gauge theories. The effective action derived in the strong coupling limit gives qualitatively plausible behavior for the deconfinement transition at finite temperature. We can apply the st...

We apply optimal control theory to a generalized SEIR-type model. The proposed system has three controls, representing social distancing, preventive means, and treatment measures combat the spread of COVID-19 pandemic. analyze such problem with respect real data transmission in Italy. Our results show appropriateness model, particular number quarantined/hospitalized (confirmed infected) recover...