Results 41 to 50 of about 174,550,829 (158)

Ergodic theorems for semigroups of operators

open access: yes, 1992
We establish ergodic theorems for Eberlein-weakly almost periodic motions and almost-orbits of semigroups of operators. The results apply to solutions of a class of (generally, nonlinear) evolution equations.
W. H. Summers, W. M. Ruess
core   +1 more source

KdV limit for the Vlasov–Poisson–Landau system

open access: yesJournal of the London Mathematical Society, Volume 114, Issue 2, August 2026.
Abstract We are concerned with the fluid limit to KdV equations for the one‐dimensional Vlasov–Poisson–Landau system that describes the dynamics of ions in plasma with the electron density determined by the self‐consistent electric potential through the so‐called Boltzmann relation. Formally, it is well known that as the Knudsen number ε→0$\varepsilon \
Renjun Duan, Dongcheng Yang, Hongjun Yu
wiley   +1 more source

Unary FA-presentable semigroups [PDF]

open access: yes, 2012
Automatic presentations, also called FA-presentations, were introduced to extend nite model theory to innite structures whilst retaining the solubility of interesting decision problems.
Cain, Alan James   +3 more
core   +1 more source

Beyond Regular Semigroups [PDF]

open access: yes, 2012
The topic of this thesis is the class of weakly U-abundant semigroups. This class is very wide, containing inverse, orthodox, regular, ample, adequate, quasi-adequate, concordant, abundant, restriction, Ehresmann and weakly abundant semigroups.
Wang, Yanhui
core   +4 more sources

Advanced control of non‐isothermal axial dispersion tubular reactors with recycle‐induced state delay

open access: yesThe Canadian Journal of Chemical Engineering, Volume 104, Issue 6, Page 3018-3037, June 2026.
Abstract We develop a delay‐aware estimation and control framework for a non‐isothermal axial dispersion tubular reactor modelled as a coupled parabolic‐hyperbolic PDE system with recycle‐induced state delay. The infinite‐dimensional dynamics are preserved without spatial discretization by representing the delay as a transport PDE and adopting a late ...
Behrad Moadeli, Stevan Dubljevic
wiley   +1 more source

Long‐Time Solvability and Asymptotics for the 3D Rotating MHD Equations

open access: yesMathematische Nachrichten, Volume 299, Issue 6, Page 1480-1509, June 2026.
ABSTRACT We consider the initial value problem for the 3D incompressible rotating MHD equations around a constant magnetic field. We prove the long‐time existence and uniqueness of solutions for small viscosity coefficient and high rotating speed. Moreover, we investigate the asymptotic behavior of solutions in the limit of vanishing viscosity and fast
Hiroki Ohyama
wiley   +1 more source

From Stability to Chaos: A Complete Classification of the Damped Klein‐Gordon Dynamics

open access: yesMathematical Methods in the Applied Sciences, Volume 49, Issue 9, Page 9696-9708, June 2026.
ABSTRACT We investigate the transition between stability and chaos in the damped Klein‐Gordon equation, a fundamental model for wave propagation and energy dissipation. Using semigroup methods and spectral criteria, we derive explicit thresholds that determine when the system exhibits asymptotic stability and when it displays strong chaotic dynamics ...
Carlos Lizama   +2 more
wiley   +1 more source

Semigroups of order-decreasing transformations [PDF]

open access: yes, 2012
Let X be a totally ordered set and consider the semigroups of orderdecreasing (increasing) full (partial, partial one-to-one) transformations of X. In this Thesis the study of order-increasing full (partial, partial one-to-one) transformations has been
Umar, Abdullahi
core   +2 more sources

Spreading Speed for a Vector‐Borne Disease System on Non‐Coincident Straight Infinite Cylinders

open access: yesStudies in Applied Mathematics, Volume 156, Issue 6, June 2026.
ABSTRACT Vector‐borne diseases remain an increasing global public health concern. In this work, we investigate the spreading speed of vector‐borne disease via a four‐component reaction–diffusion system posed on non‐coincident straight infinite cylinders, which stands for an unconventional spatial configuration.
Arnaud Ducrot   +2 more
wiley   +1 more source

Existence of viscosity solutions to abstract Cauchy problems via nonlinear semigroups

open access: yesBulletin of the London Mathematical Society, Volume 58, Issue 5, May 2026.
Abstract In this work, we provide conditions for nonlinear monotone semigroups on locally convex vector lattices to give rise to a generalized notion of viscosity solutions to a related nonlinear partial differential equation. The semigroup needs to satisfy a convexity estimate, so called K$K$‐convexity, with respect to another family of operators ...
Fabian Fuchs, Max Nendel
wiley   +1 more source

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