Linear Hamiltonian systems on time scales: positivity of quadratic functionals

• Autoři: HILSCHER Roman
• Rok publikování: 2000
• Druh: Článek v odborném periodiku
• Časopis / Zdroj: Mathematical and Computer Modelling
• Fakulta / Pracoviště MU: Přírodovědecká fakulta
• Obor: Obecná matematika
• Klíčová slova: time scale; (continuous and discrete) linear Hamiltonian system; disconjugacy; principal solution; quadratic functional

Popis

In this work we consider a linear Hamiltonian system (H)

x^\Delta = A_t x^\sigma + B_t u,
u^\Delta = -C_t x^\sigma - A_t^T u

on an arbitrary time scale T, which allows (among others)

• to treat both continuous and discrete linear Hamiltonian systems (as the special cases for T=R and T=Z) within one theory;
• to explain the discrepancies between these two theories while studying systems of the form (H).

As a main result we prove that disconjugacy of the system (H) is a sufficient condition for positive definiteness of the quadratic functional associated with (H). The principal tool is the Picone identity on T. We derive also the corresponding Wronskian identity, Riccati equation in this general setting on time scales.

Související projekty

• Diferenciální a funkcionálně-diferenciální rovnice
• Diferenční rovnice a jejich aplikace