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A role of the coefficient of the differential term in qualitative theory of half-linear equations

Pavel Řehák (2010)

Mathematica Bohemica

The aim of this contribution is to study the role of the coefficient r in the qualitative theory of the equation ( r ( t ) Φ ( y Δ ) ) Δ + p ( t ) Φ ( y σ ) = 0 , where Φ ( u ) = | u | α - 1 sgn u with α > 1 . We discuss sign and smoothness conditions posed on r , (non)availability of some transformations, and mainly we show how the behavior of r , along with the behavior of the graininess of the time scale, affect some comparison results and (non)oscillation criteria. At the same time we provide a survey of recent results acquired by sophisticated modifications of the Riccati...

A simple method for constructing non-liouvillian first integrals of autonomous planar systems

Axel Schulze-Halberg (2006)

Czechoslovak Mathematical Journal

We show that a transformation method relating planar first-order differential systems to second order equations is an effective tool for finding non-liouvillian first integrals. We obtain explicit first integrals for a subclass of Kukles systems, including fourth and fifth order systems, and for generalized Liénard-type systems.

A simple model of thermoelectric oscillations

Giovanni Cimatti, Eduard Feireisl (1995)

Applications of Mathematics

A system of ordinary differential equations modelling an electric circuit with a thermistor is considered. Qualitative properties of solution are studied, in particular, the existence and nonexistence of time-periodic solutions (the Hopf bifurcation).

A singular version of Leighton's comparison theorem for forced quasilinear second order differential equations

Ondřej Došlý, Jaroslav Jaroš (2003)

Archivum Mathematicum

We extend the classical Leighton comparison theorem to a class of quasilinear forced second order differential equations ( r ( t ) | x ' | α - 2 x ' ) ' + c ( t ) | x | β - 2 x = f ( t ) , 1 < α β , t I = ( a , b ) , ( * ) where the endpoints a , b of the interval I are allowed to be singular. Some applications of this statement in the oscillation theory of (*) are suggested.

A stochastic min-driven coalescence process and its hydrodynamical limit

Anne-Laure Basdevant, Philippe Laurençot, James R. Norris, Clément Rau (2011)

Annales de l'I.H.P. Probabilités et statistiques

A stochastic system of particles is considered in which the sizes of the particles increase by successive binary mergers with the constraint that each coagulation event involves a particle with minimal size. Convergence of a suitably renormalized version of this process to a deterministic hydrodynamical limit is shown and the time evolution of the minimal size is studied for both deterministic and stochastic models.

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