Institute of Mathematics AS CR, v. v. i.
Not a member yet
44818 research outputs found
Sort by
An improved oscillation theorem for nonlinear differential equations of advanced type
Get PDFsummary:This paper deals with the oscillatory solutions of the first order nonlinear advanced differential equation. The aim of the present paper is to obtain an oscillation condition for this equation. This result is new and improves and correlates many of the well-known oscillation criteria that were in the literature. Finally, an example is given to illustrate the main result
Packing of non-blocking four-dimensional cubes into the unit cube
Get PDFsummary:Any collection of non-blocking four-dimensional cubes, whose total volume does not exceed 17/81, can be packed into the unit four-dimensional cube. This bound is tight for the parallel packing
Weak solvability and numerical analysis of a class of time-fractional hemivariational inequalities with application to frictional contact problems
No full textsummary:We investigate a generalized class of fractional hemivariational inequalities involving the time-fractional aspect. The existence result is established by employing the Rothe method in conjunction with the surjectivity of multivalued pseudomonotone operators and the properties of the Clarke generalized gradient. We are also exploring a numerical approach to address the problem, utilizing both spatially semi-discrete and fully discrete finite elements, along with a discrete approximation of the fractional derivative. All these results are applied to the analysis and numerical approximations of a frictional contact model that describes the quasi-static contact between a viscoelastic body and a solid foundation. The constitutive relation is modeled using the fractional Kelvin-Voigt law. The contact and friction are described by the subdifferential boundary conditions. The variational formulation of this problem leads to a fractional hemivariational inequality. The error estimates for this problem are derived. Finally, here's a second concrete example to illustrate the application. We propose a frictional contact model that incorporates normal compliance and Coulomb friction to describe the quasi-static contact between a viscoelastic body and a solid foundation
Global classical solutions in a self-consistent chemotaxis(-Navier)-Stokes system
No full textsummary:The self-consistent chemotaxis-fluid system is considered under no-flux boundary conditions for and the Dirichlet boundary condition for on a bounded smooth domain , . The existence of global bounded classical solutions is proved under a smallness assumption on . \endgraf Both the effect of gravity (potential force) on cells and the effect of the chemotactic force on fluid are considered here, and thus the coupling is stronger than the most studied chemotaxis-fluid systems. The literature on self-consistent chemotaxis-fluid systems of this type so far concentrates on the nonlinear cell diffusion as an additional dissipative mechanism. To the best of our knowledge, this is the first result on the boundedness of a self-consistent chemotaxis-fluid system with linear cell diffusion
On a theorem of McCoy
Get PDFsummary:We study McCoy's theorem to the skew Hurwitz series ring for some different classes of rings such as: semiprime rings, APP rings and skew Hurwitz serieswise quasi-Armendariz rings. Moreover, we establish an equivalence relationship between a right zip ring and its skew Hurwitz series ring in case when a ring satisfies McCoy's theorem of skew Hurwitz series
Oscillation of second-order quasilinear retarded difference equations via canonical transform
Get PDFsummary:We study the oscillatory behavior of the second-order quasi-linear retarded difference equation under the condition (i.e., the noncanonical form). Unlike most existing results, the oscillatory behavior of this equation is attained by transforming it into an equation in the canonical form. Examples are provided to show the importance of our main results
New kinds of hybrid filters of EQ-algebras
Get PDFsummary:The main goal of this paper is to introduce hybrid positive implicative and hybrid implicative (pre)filters of EQ-algebras. In the following, some characterizations of this hybrid (pre)filters are investigated and it is proved that the quotient algebras induced by hybrid positive implicative filters in residuated EQ-algebras are idempotent and residuated EQ-algebra. Moreover, the relationship between hybrid implicative prefilters and hybrid positive implicative prefilters are discussed and it is shown that these concepts coincide in good involutive EQ-algebras. Finally, it is proved that the quotient EQ-algebra respect to a hybrid positive implicative filter is involutive if and only if the hybrid filter is hybrid implicative filter
Quantization of semisimple real Lie groups
Get PDFsummary:We provide a novel construction of quantized universal enveloping -algebras of real semisimple Lie algebras, based on Letzter’s theory of quantum symmetric pairs. We show that these structures can be ‘integrated’, leading to a quantization of the group C-algebra of an arbitrary semisimple algebraic real Lie group