Vzestup české fyziky na přelomu 19. a 20. století je neodmyslitelně spjat s činností jedné velké osobnosti, zakladatele Fysikálního ústavu české university v Praze Čeňka Strouhala .Od jeho narození uplynulo 10. dubna 2010 právě 160 let., Jan Valenta., and Obsahuje bibliografii
We study an example in two dimensions of a sequence of quadratic functionals whose limit energy density, in the sense of Γ-convergence, may be characterized as the dual function of the limit energy density of the sequence of their dual functionals. In this special case, Γ-convergence is indeed stable under the dual operator. If we perturb such quadratic functionals with linear terms this statement is no longer true.
We build the flows of non singular Morse-Smale systems on the 3-sphere from its round handle decomposition. We show the existence of flows corresponding to the same link of periodic orbits that are non equivalent. So, the link of periodic orbits is not in a 1-1 correspondence with this type of flows and we search for other topological invariants such as the associated dual graph.
In this paper we initiate the study of total restrained domination in graphs. Let $G=(V,E)$ be a graph. A total restrained dominating set is a set $S\subseteq V$ where every vertex in $V-S$ is adjacent to a vertex in $S$ as well as to another vertex in $V-S$, and every vertex in $S$ is adjacent to another vertex in $S$. The total restrained domination number of $G$, denoted by $\gamma _r^t(G)$, is the smallest cardinality of a total restrained dominating set of $G$. First, some exact values and sharp bounds for $\gamma _r^t(G)$ are given in Section 2. Then the Nordhaus-Gaddum-type results for total restrained domination number are established in Section 3. Finally, we show that the decision problem for $\gamma _r^t(G)$ is NP-complete even for bipartite and chordal graphs in Section 4.