Institute of Mathematics AS CR, v. v. i.
Not a member yet
44818 research outputs found
Sort by
Homogenization of monotone parabolic problems with an arbitrary number of spatial and temporal scales
No full textsummary:We prove a general homogenization result for monotone parabolic problems with an arbitrary number of microscopic scales in space as well as in time, where the scale functions are not necessarily powers of the scale parameter . The main tools for the homogenization procedure are multiscale convergence and very weak multiscale convergence, both adapted to evolution problems
A new block triangular preconditioner for three-by-three block saddle-point problem
No full textsummary:In this paper, to solve the three-by-three block saddle-point problem, a new block triangular (NBT) preconditioner is established, which can effectively avoid the solving difficulty that the coefficient matrices of linear subsystems are Schur complement matrices when the block preconditioner is applied to the Krylov subspace method. Theoretical analysis shows that the iteration method produced by the NBT preconditioner is unconditionally convergent. Besides, some spectral properties are also discussed. Finally, numerical experiments are provided to show the effectiveness of the NBT preconditioner
On feebly nil-clean rings
No full textsummary:A ring is feebly nil-clean if for any there exist two orthogonal idempotents and a nilpotent such that . Let be a 2-primal feebly nil-clean ring. We prove that every matrix ring over is feebly nil-clean. The result for rings of bounded index is also obtained. These provide many classes of rings over which every matrix is the sum of orthogonal idempotent and nilpotent matrices
Hall algebras of two equivalent extriangulated categories
No full textsummary:For any positive integer , let be a linearly oriented quiver of type with vertices. It is well-known that the quotient of an exact category by projective-injectives is an extriangulated category. We show that there exists an extriangulated equivalence between the extriangulated categories and , where and are the two extriangulated categories corresponding to the representation category of and the morphism category of projective representations of , respectively. As a by-product, the Hall algebras of and are isomorphic. As an application, we use the Hall algebra of to relate with the quantum cluster algebras of type
Scholars of Rudolphine Prague
No full textsummary:V článku představíme některé zajímavosti spjaté s proslulými osobnostmi vědeckého života renesanční rudolfínské Prahy. Budou to Martin Bacháček, Tadeáš Hájek z Hájku, Tycho Brahe, Johannes Kepler, David Gans a Joost Bürgi
Interview with Prof. Ivan Netuka
No full textsummary:Profesor Ivan Netuka (7. 7. 1944 -- 14. 10. 2020) byl významnou osobností československé a české matematiky, výjimečným a dobrým člověkem. Rozhovor, který vznikl v říjnu 2019, připomíná jeho nedožité osmdesáté narozeniny
A new approach for fuzzy gyronorms on gyrogroups and its fuzzy topologies
Get PDFsummary:In this paper, a new approach for fuzzy gyronorms on gyrogroups is presented. The relations between fuzzy metrics(in the sense of Morsi), fuzzy gyronorms, gyronorms on gyrogroups are studied. Also, some sufficient conditions, which can make a fuzzy normed gyrogroup to be a topological gyrogroup and a fuzzy topological gyrogroup, are found. Meanwhile, the relations between topological gyrogroups, fuzzy topological gyrogroups and stratified fuzzy topological gyrogroups are studied. Finally, the properties of fuzzifying topological gyrogroups are studied