Hamilton cycles in 5-connected line graphs

A conjecture of Carsten Thomassen states that every 4-connected line graph is hamiltonian. It is known that the conjecture is true for 7-connected line graphs. We improve this by showing that any 5-connected line graph of minimum degree at least 6 is hamiltonian. The result extends to claw-free graphs and to Hamilton-connectedness

Quasigraphs and skeletal partitions

We give a new proof of the Skeletal Lemma, which is the main technical tool in our paper on Hamilton cycles in line graphs [T. Kaiser and P. Vr\'ana, Hamilton cycles in 5-connected line graphs, European J. Combin. 33 (2012), 924-947]. It generalises results on disjoint spanning trees in graphs to the context of 3-hypergraphs. The lemma is proved in a slightly stronger version that is more suitable for applications. The proof is simplified and formulated in a more accessible way

Guangdong-Hong Kong School Martial Arts Fiction

This thesis deals with the "Guangdong-Hong Kong Martial Arts Fiction School" (Yue Gang pai jiji xiaoshuo 粵港派技擊小說), a specific subgenre of Chinese fiction that was popular from the 1930s till the 1960s. Stories, whose protagonists are most often legendary Southern Shaolin heroes and historical masters and practitioners of Chinese martial arts, were published mostly in Cantonese and Hong Kong newspapers as serialized fiction. The Guangdong-Hong Kong Martial Arts Fiction School is usually considered as one of the subgenres of wuxia (武俠) fiction and it is still insufficiently explored. The Guangdong-Hong Kong martial arts novels, which show many features of junk fiction, increased readers' patriotic feelings, contributed to the promotion of martial arts masters, and reinforced some common ideas about Chinese martial arts, which can still be found in today's society. In this thesis, we put the discussed subgenre in its social and literary-historical context, describe its genesis, discuss the thematic areas and narrative form of Guangdong-Hong Kong martial arts fiction, and introduce three representative authors of Guangdong-Hong Kong Martial Arts Fiction School and some protagonists of selected proses. The main part of this thesis is a literary analysis focused on the definition of the most distinctive...Diplomová práce pojednává o "Kantonsko-hongkongské škole příběhů ze světa umění boje" (Yue Gang pai jiji xiaoshuo 粵港派技擊小說), specifickém proudu čínské literatury třicátých až šedesátých let 20. století. Příběhy, jejichž protagonisty jsou nejčastěji legendární osobnosti kláštera Jižní Shaolin či historicky doložení mistři a cvičenci čínských bojových umění, vycházely jako romány na pokračování, popř. též jako povídky, především v kantonských a hongkongských periodikách. Kantonsko-hongkongská škola příběhů ze světa umění boje bývá považována za jeden ze subžánrů literatury wuxia (武俠), o němž se ve stávajících studiích hovoří zřídka. Povídky a romány ze světa umění boje, vykazující řadu rysů brakové literatury, působily na vlastenecké cítění čtenářů, podílely se na propagaci dobových mistrů a na upevnění některých stereotypních představ, s nimiž jsou čínská bojová umění dodnes spojována. Práce zasazuje subžánr do dobového společenského a literárně-historického kontextu, nastiňuje jeho genezi, pojednává o tematickém zaměření a narativní formě příběhů ze světa umění boje a blíže představuje reprezentativní autory a vybrané protagonisty zkoumaných příběhů. Stěžejní část práce tvoří literárněvědná analýza zaměřená na pojmenování charakteristických znaků subžánru, výčet typických motivů a identifikaci...Katedra sinologieDepartment of SinologyFaculty of ArtsFilozofická fakult

Packing TT-connectors in graphs needs more connectivity

Strengthening the classical concept of Steiner trees, West and Wu [J. Combin. Theory Ser. B 102 (2012), 186--205] introduced the notion of a $T$-connector in a graph $G$ with a set $T$ of terminals. They conjectured that if the set $T$ is $3k$-edge-connected in $G$, then $G$ contains $k$ edge-disjoint $T$-connectors. We disprove this conjecture by constructing infinitely many counterexamples for $k=1$ and for each even $k$

On 1-Hamilton-connected claw-free graphs

A graph G is k-Hamilton-connected (k-hamiltonian) if G−X is Hamilton-connected (hamiltonian) for every set X ⊂ V (G) with |X| = k. In the paper, we prove that (i) every 5-connected claw-free graph with minimum degree at least 6 is 1-Hamilton-connected, (ii) every 4-connected claw-free hourglass-free graph is 1-Hamilton-connected. As a byproduct, we also show that every 5-connected line graph with minimum degree at least 6 is 3-hamiltonian

Vanadium redox flow battery - membrane selection and characterization

The increasing share of renewable energy sources in the total energy production emphasizes the need for a reliable and cheap stationary energy storage. Such a tool allows to baffle hardly predictable non-stabilities in output power of photovoltaics or wind turbines on the power transmission level. Vanadium redox flow battery (VRFB) appears as a promising solution for the stationary energy storage as it offers high efficiency (80% DC-DC), foolproof arrangement of decoupled power (kW) to capacity (kWh), extended durability and fast demand response. However, the broader commercialization of the technology is still obstructed by relatively high investment costs. In redox flow batteries, electrolytes are not stored in the battery construction but in an external tank and are continuously pumped through the battery stack where electrical energy is transformed on inert electrodes into chemical during charging and conversely during discharging. Battery stack is composed of several serially connected cells. Each cell consists of positive and negative half-cells which are mutually separated typically by ion-exchange membrane. In VRFB, both electrolytes comprises vanadium salts dissolved in diluted sulfuric acid (i.e., (VO2)2SO4 and VOSO4 in positive electrolyte and VSO4 and V2(SO4)3 in negative electrolyte). Price of the ion-exchange membrane, one of the key components of the battery stack, represents 5 - 15 % of the overall costs typically. Long term durability of membrane in acidic electrolytes is vitally necessary for VRFB function. Please click Additional Files below to see the full abstract