Results 21 to 30 of about 10,383,907 (288)

Conserved- and zero-mean quadratic quantities in oscillatory systems

open access: yes, 2005
We study quadratic functionals of the variables of a linear oscillatory system and their derivatives. We show that such functionals are partitioned in conserved quantities and in trivially- and intrinsic zero-mean quantities.
Willems, Jan C., Rapisarda, Paolo
core   +2 more sources

Symmetry of Quadratic Homogeneous Differential Systems

open access: yes, 2008
10 ...
Nadjafikhah, Mehdi   +1 more
openaire   +2 more sources

Phase portraits of two classes of quadratic differential systems exhibiting as solutions two cubic algebraic curves

open access: yesDemonstratio Mathematica, 2023
The classification of the phase portraits is one of the classical and difficult problems in the qualitative theory of polynomial differential systems in R2{{\mathbb{R}}}^{2}, particularly for quadratic systems.
Benterki Rebiha, Belfar Ahlam
doaj   +1 more source

Linear Hamiltonian behaviors and bilinear differential forms [PDF]

open access: yes, 2004
We study linear Hamiltonian systems using bilinear and quadratic differential forms. Such a representation-free approach allows us to use the same concepts and techniques to deal with systems isolated from their environment and with systems subject to ...
Rapisarda, P.   +7 more
core   +3 more sources

Analytic integrability of quadratic–linear polynomial differential systems [PDF]

open access: yesErgodic Theory and Dynamical Systems, 2009
AbstractFor the quadratic–linear polynomial differential systems with a finite singular point, we classify the ones which have a global analytic first integral, and provide the explicit expression of their first integrals.
Llibre, Jaume, Valls, Clàudia
openaire   +2 more sources

On positive-realness and stability of switched linear differential systems

open access: yes, 2013
We present some results regarding the stability of switched linear differential systems (SLDS) in the behavioral framework. Positive-realness is studied as a sufficient condition for stability and some implications derived from the use of positive-real ...
Paolo Rapisarda   +3 more
core   +2 more sources

Explicitly solvable systems of two autonomous first-order Ordinary Differential Equations with homogeneous quadratic right-hand sides [PDF]

open access: yesOpen Communications in Nonlinear Mathematical Physics, 2021
After tersely reviewing the various meanings that can be given to the property of a system of nonlinear ODEs to be solvable, we identify a special case of the system of two first-order ODEs with homogeneous quadratic right-hand sides which is explicitly ...
Francesco Calogero, Farrin Payandeh
doaj   +1 more source

Rigid Polynomial Differential Systems with Homogeneous Nonlinearities

open access: yesMathematics
Planar differential systems whose angular velocity is constant are called rigid or uniform differential systems. The first rigid system goes back to the pendulum clock of Christiaan Huygens in 1656; since then, the interest for the rigid systems has been
Jaume Llibre
doaj   +1 more source

Quadratic systems with two invariant real straight lines and an invariant parabola

open access: yesElectronic Journal of Qualitative Theory of Differential Equations
After the linear differential systems in the plane the easiest ones are the quadratic polynomial differential systems. Due to their nonlinearity and also to their many applications these systems have been studied by many authors. Let QS denote the set of
Jaume Llibre, Huaxin Ou
doaj   +1 more source

Higher-order linear lossless systems

open access: yes, 2008
We define a lossless autonomous system as one having a quadratic differential form associated with it called the total energy, which obeys the property of positivity and which is conserved.
Rao, Shodhan, Rapisarda, Paolo
core   +2 more sources

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