2014-11-10 10:00-10:45 FAMNIT-SEMIN prof. dr. Tomaž Pisanski General Haar graphs in sage We implemented several programs that may deal with general Haar graphs. The programs are written in Python but embedded in the system sage. A Haar graph is a…
2014-11-03 10:00-10:45 FAMNIT-SEMIN dr. Rok Požar Solvable regular covering projections of graphs We present basic properties of universal covering projections and exploit them in order to develop an algorithm for computing all solvable regular covering projections of a given graph admitting a lift of…
2014-10-27 10:00-10:45 FAMNIT-SEMIN Istvan Kovacs (UP FAMNIT) Finite CI-groups and Schur rings A Cayley graph Cay(G,S) is called a CI-graph if for every subset Tof G, if Cay(G,T) and Cay(G,S) are isomorphic, then T=f(S) for some automorphism f of G.…
2014-10-20 10:00-10:45 FAMNIT-SEMIN Ademir Hujdurović Generalized Cayley graphs Generalized Cayley graphs were defined by D.Marušič, R. Scapellato and N. Zagaglia Salvi in 1992. They studied properties of such graphs, mostly related to double coverings of graph. They also posed a…
2014-10-13 10:00-10:45 FAMNIT-SEMIN György Pál Gehér (University of Szeged and University of Debrecen, Hungary) A two dimensional matrix problem of Molnar and Timmermann and its connection to a geometric problem problem of Rassias and Wagner Download abstract. Download slides.
2014-10-06 11:00-12:00 FAMNIT-SEMIN Dr. Pablo De Caria (National University of La Plata, Argentina) On chordal and dually chordal graphs and their tree representations Chordal and dually chordal graphs are well known classes, whose duality becomes evident by the use of…
2014-10-06 10:00-11:00 FAMNIT-SEMIN Dr. Flavia Bonomo (Buenos Aires University, Argentina) Minimum weight clique cover in claw-free perfect graphs For a perfect graph G, and given a weight function w on the vertices of G, linear programming duality ensures that the weight of…
2014-09-29 10:00-11:00 FAMNIT-SEMIN Dr Matthew Johnson (Durham University, UK) Finding (Shortest) Paths between Graph Colourings The reconfiguration graph of the $k$-colourings of a graph $G$ contains as its vertex set the proper vertex $k$-colourings of $G$, and two colourings are…
2014-06-16 10:00-12:00 FAMNIT-MP Janez Povh (Fakulteta za informacijske študije v Novem mestu) Kaj imata skupnega kombinatorična optimizacija in realna algebraična geometrija V kombinatorični optimizaciji se ukvarjamo z iskanjem optimuma linearne ali kvadratične funkcije nad končno množico, ki pa je praviloma…
2014-06-02 10:00-11:00 FAMNIT-SEMIN Dr. Russ Woodroofe ( Mississippi State University, USA) Noncontractibility of the coset lattice and fixed points of group actions Ken Brown asked whether there is any group G such that the coset lattice of G is contractible.…