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Záznamy kolekce (řazeno podle Datum zaslání v sestupně pořadí): 1 až 20 z 99
Bobkov, Vladimír , Drábek, Pavel , Ilyasov, Yavdat
On full Zakharov equation and its approximations

We study the solvability of the Zakharov equation in a bounded domain under homogeneous Dirichlet or Navier boundary conditions. This problem is a consequence of the system of equations derived by Zakharov to model the Langmuir collapse in plasma physics. Assumptions for the existe...

Procházková, Petra , Roubalová, Radka , Dvořák, Jiří , Tlaskalová-Hogenová, Helena , Čermáková, Martina , Tomášová, Petra , Šedivá, Blanka , Kuzma, Marek , Bulant, Josef , Bilej, Martin , Hrabák, Pavel , Meisnerova, Eva , Lambertová, Alena , Papežová, Hana
Microbiota, Microbial Metabolites, and Barrier Function in A Patient with Anorexia Nervosa after Fecal Microbiota Transplantation

The change in the gut microbiome and microbial metabolites in a patient suffering from severe and enduring anorexia nervosa (AN) and diagnosed with small intestinal bacterial overgrowth syndrome (SIBO) was investigated. Microbial gut dysbiosis is associated with both AN and SIBO, and th...

Bizzarri, Michal , Lávička, Miroslav , Vršek, Jan
Computing projective equivalences of special algebraic varieties

This paper is devoted to the investigation of selected situations when computing projective (and other) equivalences of algebraic varieties can be efficiently solved via finding projective equivalences of finite sets of points on the projective line. In particular, we design a method th...

Pospíšil, Jan , Sobotka, Tomáš , Ziegler, Philippe
Robustness and sensitivity analyses for stochastic volatility models under uncertain data structure

In this paper, we perform robustness and sensitivity analysis of several continuous-time stochastic volatility (SV) models with respect to the process of market calibration. The analyses should validate the hypothesis on importance of the jump part in the underlying model dynamics. Also ...

Aboomahigir, Elham , Nedela, Roman
Cubic Cayley Graphs of Girth at most 6 and Their Hamiltonicity

Thomassen's conjecture states that a cubic graph with sufficiently large cyclic connectivity is hamiltonian. Even the following strong conjecture could hold: A cyclically 7-connected cubic graph is hamiltonian, or it is the Coxeter graph. Assuming the conjecture holds true, to prove the&...

Hu, Kan , Nedela, Roman , Wang, NaEr
Complete regular dessins of odd prime power

A dessin is a 2-cell embedding of a connected 2-coloured bipartite graph into an orientable closed surface. A dessin is regular if its group of colour- and orientation-preserving automorphisms acts regularly on the edges. In this paper we employ group-theoretic method to determine ...

Hu, Kan , Nedela, Roman , Wang, N.-E. , Yuan, K.
Reciprocal skew morphisms of cyclic groups

Reciprocal pairs of skew morphisms of cyclic groups are in one-to-one correspondence with isomorphism classes of regular dessins with complete bipartite underlying graphs. In this paper we determine all reciprocal pairs of skew morphisms of the cyclic groups provided that one of them&#x...

Nedela, Roman , Pomerance, Carl
Density of singular pairs of integers

An ordered pair of integers (m,n) is called singular if g.c.d.(m,\phi(n))=1=g.c.d.(\phi(m),n), a concept which is relevant to pairwise products of cyclic groups. In this note we show that the number of singular pairs is asymptotic to z(x)^2, where z(x) is a function derived&#x...

Cooper, Jacob W. , Kaiser, Tomáš , Král', Daniel , Noel, Jonathan A.
Weak regularity and finitely forcible graph limits

Graphons are analytic objects representing limits of convergent sequences of graphs. Lovász and Szegedy conjectured that every finitely forcible graphon, i.e. any graphon determined by finitely many subgraph densities, has a simple structure. In particular, one of their conjectures would imply&#x...

Hoffmann-Ostenhof, Arthur , Kaiser, Tomáš , Ozeki, Kenta
Decomposing planar cubic graphs

The 3‐Decomposition Conjecture states that every connected cubic graph can be decomposed into a spanning tree, a 2‐regular subgraph and a matching. We show that this conjecture holds for the class of connected plane cubic graphs.

Stehlík, Petr
Matematika za karetní hrou dobble

In this paper we deal with the connection of the pouplar card game dobble with combinatorial structures. We show that the existence of perfect decks of cards is connected to the existence of finite projective planes and systems of ortogonal Latin squares. Next, we use a&#...

Hupkes, Hermen Jan , Morelli, Leonardo , Stehlík, Petr
Bichromatic Travelling Waves for Lattice Nagumo Equations

We discuss bichromatic (two-color) front solutions to the bistable Nagumo lattice differential equation. Such fronts connect the stable spatially homogeneous equilibria with spatially heterogeneous 2-periodic equilibria and hence are not monotonic like the standard monochromatic fronts. We provide explicit...

Hupkes, Hermen Jan , Morelli, Leonardo , Stehlík, Petr , Švígler, Vladimír
Multichromatic travelling waves for lattice Nagumo equations

We discuss multichromatic front solutions to the bistable Nagumo lattice differential equation. Such fronts connect the stable spatially homogeneous equilibria with spatially heterogeneous n -periodic equilibria and hence are not monotonic like the standard monochromatic fronts. In contrast to the...

Hošek, Radim , Volek, Jonáš
Discrete advection–diffusion equations on graphs: Maximum principle and finite volumes

We study an initial value problem for explicit and implicit difference advection–diffusion equations on graphs. Problems on both finite and infinite graphs are considered. We analyze the existence and uniqueness of solutions. Interestingly, we show that there exist infinitely many solutions ...

Tomášová, Petra , Bugáňová, Martina , Pelantová, Helena , Holubová, Martina , Šedivá, Blanka , Železná, Blanka , Haluzík, Martin , Maletínská, Lenka , Kuneš, Jaroslav , Kuzma, Marek
Metabolomics Based on MS in Mice with Diet-Induced Obesity and Type 2 Diabetes Mellitus: the Effect of Vildagliptin, Metformin, and Their Combination

Type 2 diabetes mellitus (T2DM) is a major epidemiological problem. Metformin and vildagliptin are well-established antidiabetic drugs. The aim of the study was to evaluate the changes of plasma metabolic profile induced by a high-fat diet (HFD) and subsequent oral administration of met...

Chhetri, Maya , Drábek, Pavel , Shivaji, Ratnasingham
S-shaped bifurcation diagrams in exterior domains

We study a nonlinear eigenvalue problem on the exterior to a simply connected bounded domain inRN containing the origin.We consider positive weak solutions satisfying Dirichlet boundary conditions on the compact boundary and decaying to zero at infinity. We discuss multiplicity and uniquenes...

Kaiser, Tomáš , Lukoťka, Robert , Máčajová, Edita , Rollová, Edita
Shorter signed circuit covers of graphs

A signed circuit is a minimal signed graph (with respect to inclusion) that admits a nowhere-zero flow. We show that each flow-admissible signed graph on m edges can be covered by signed circuits of total length at most (3+2/3)m, improving a recent result of Cheng et...

Chlebicka, Iwona , Drábek, Pavel , Kalamajska, Agnieszka
Caccioppoli-type estimates and Hardy-type inequalities derived from weighted p-harmonic problems

We obtain Caccioppoli-type estimates for nontrivial and nonnegative solutions to anticoercive partial differential inequalities of elliptic type involving weighted p-Laplacian. Using Caccioppoli-type estimates, we obtain several variants of Hardy-type inequalities in weighted Sobolev spaces.

Bizzarri, Michal , Lávička, Miroslav , Vršek, Jan
Linear computational approach to interpolations with polynomial Minkowski Pythagorean hodograph curves

Methods using Pythagorean hodographs both in Euclidean plane and Minkowski space are often used in geometric modelling when necessary to solve the problem of rationality of offsets of planar domains. A main justification for studying and formulating approximation and interpolation algorithms ...

Drábek, Pavel , Hernández, Jesús
Quasilinear eigenvalue problems with singular weights for the p-Laplacian

In this paper we study quasilinear homogeneous eigenvalue problem with the p-Laplacian involving singular weights. We work on a bounded domain with Lipschitzian boundary and the weights are negative powers of the distance from the boundary. We generalize results concerning the existence ...

Záznamy kolekce (řazeno podle Datum zaslání v sestupně pořadí): 1 až 20 z 99