Matematický ústav

Nejnovější přírůstky:
2018-03-16
15:47
Problem posing in prospective primary school teachers´ education: Case of Concept Cartoons
Hošpesová, A. ; Tichá, Marie
The presentation will discuss creation of Concept Cartoons as a possible way to support the development and refinement of prospective primary teachers' pedagogical concept knowledge.

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2018-03-09
13:20
Genus two prime form formula for vertex operator characters
Zuevsky, Alexander
We find an expression for the self-sewn genus two Riemann surface counterpart of the torus formula for for an $n$-vertex operator character for the Heisenberg vertex operator algebra an $n$-point correlation function for a vertex operator algebra module with complex parameterization of corresponding states.

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2018-03-09
13:20
Higher dimensional Robinson-Trautman spacetimes sourced by p-forms: static and radiating black holes
Ortaggio, Marcello ; Podolský, J. ; Žofka, M.
We summarize results about Robinson-Trautman spacetimes in the presence of an aligned p-form Maxwell field and an arbitrary cosmological constant in n >= 4 dimensions. While in odd dimensions the solutions reduce to static black holes dressed with an electric and a magnetic field (with an Einstein space horizon), in even dimensions 2p = n they may also describe black holes gaining (or losing) mass by receiving (or emitting) electromagnetic radiation. The Weyl type of the spacetimes is also briefly discussed in all the possible cases.

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2018-03-09
13:20
Courant algebroid connections and string effective actions
Jurčo, B. ; Vysoký, Jan
Courant algebroids are a natural generalization of quadratic Lie algebras, appearing in various contexts in mathematical physics. A connection on a Courant algebroid gives an analogue of a covariant derivative compatible with a given fiber-wise metric. Imposing further conditions resembling standard Levi-Civita connections, one obtains a class of connections whose curvature tensor in certain cases gives a new geometrical description of equations of motion of low energy effective action of string theory. Two examples are given. One is the so called symplectic gravity, the second one is an application to the the so called heterotic reduction. All necessary definitions, propositions and theorems are given in a detailed and self-contained way.

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2018-03-09
13:20
Clusterization of correlation functions
Zuevsky, Alexander
Using the Zhu recursion formulas for correlation functions for vertex operator algebras, we introduce a cluster algebra structure over a non-commutative set of variables.

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2018-03-09
13:20
Crandall-Rabinowitz type bifurcation for non-differentiable perturbations of smooth mappings
Recke, L. ; Väth, Martin ; Kučera, Milan ; Navrátil, J.
We consider abstract equations of the type ..., where lambda is a bifurcation parameter and tau is a perturbation parameter. We suppose that ... for all lambda and tau, F is smooth and the unperturbed equation ... describes a Crandall-Rabinowitz bifurcation in lambda=0, that is, two half-branches of nontrivial solutions bifurcate from the trivial solution in lambda=0. Concerning G, we suppose only a certain Lipschitz condition; in particular, G is allowed to be non-differentiable. We show that for fixed small ... there exist also two half-branches of nontrivial solutions to the perturbed equation, but they bifurcate from the trivial solution in two bifurcation points, which are different, in general. Moreover, we determine the bifurcation directions of those two half-branches, and we describe, asymptotically as ..., how the bifurcation points depend on tau. Finally, we present applications to boundary value problems for quasilinear elliptic equations and...

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2018-03-09
13:19
Sine-Gordon model in the homogeneous higher grading
Zuevsky, Alexander
A construction of equations and solutions for the sine-Gordon model in the homogeneous grading as an example of higher grading a ne Toda models are considered.

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2018-03-09
13:19
Average contra-rotation and co-rotation of line segments for flow field analysis
Šístek, Jakub ; Kolář, Václav
The earlier concept of the average co-rotation of infinitesimal radial line segments near a point is extended to the case of contra-rotation. The tensor of the contra-rotation is introduced and averaged over "all planar cross sections" going through the examined point. Both the average contra-rotation and co-rotation, representing shear-free quantities, are applied to describe a complex flow structure.

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2018-03-09
13:19
The effect of irregular interfaces on the BDDC method for the Navier-Stokes equations
Hanek, M. ; Šístek, Jakub ; Burda, P.
We investigate the effect of interface irregularity on the convergence of the BDDC method for Navier-Stokes equations. A benchmark problem of a sequence of contracting channels is proposed to evaluate the robustness of the iterative solver with respect to element aspect ratios at the interface. Partitioners based on graph of the mesh and the geometry of the domain are compared. It is shown, that the convergence is significantly improved by avoiding irregular interfaces for the benchmark problem as well as for an industrial problem of oil flow in hydrostatic bearing.

Úplný záznam
2018-03-09
13:19
Observing how future primary school teachers reason and generalize: the case of number triangles and Concept Cartoons
Samková, L. ; Tichá, Marie
The contribution focuses on the possibility to use an educational tool called Concept Cartoons as a diagnostic instrument in problem solving and problem posing activities of future primary school teachers. The aim of the presented study is to observe which aspects of future primary school teachers' knowledge related to reasoning and generalization could be investigated through Concept Cartoons that are based on a substantial learning environment called "Number triangles".

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