U četvrtak, 3. rujna 2026, od 15 do 19 sati, u predavaonici 121 Građevinskog fakulteta u Kačićevoj 26, u okviru Seminara za kombinatornu i diskretnu matematiku održat će se četiri predavanja:

1. Lingjian Shi (Northwestern Polytechnic University, Xi'an, Kina): Some works of maximal matchings in graphs

Sažetak: A matching of graph G is maximal if it cannot be expanded by adding any edge to create a larger matching. Doslic et al. obtained general generating functions for the numbers of maximal matchings in three classes of benzenoid chains. By using the Hosoya vector and k-matching vector, Cruz et al. and Oz et al. researched the Hosoya index and the k-matching number of benzenoids, respectively. Inspired by these results, by using the maximal matching vector, we show that the number of maximal matchings of a benzenoid chain with n hexagons equals to the product of n certain matrices, each of which is S, L or R according to the type of the connection mode of the benzenoid chain. And by applying the perfect matching vector and maximal matching vector to a path of a double hexagonal chain, we obtained the numbers of perfect matchings and maximal matchings of a double hexagonal chain with n naphthalenes. For a hexagonal ring H with n hexagons, we show that the number of maximal matchings of H equals the trace of the product of n matrices, each of which is also S, L or R according to the type of the connection mode of H. Finally, we extend this conclusion to a

2. Wei Li (Northwestern Polytechnic University, Xi'an, Kina): Perfect Matchings in Open and Cyclic Chain Graphs

Sažetak: We develop a unified transfer-matrix framework for counting perfect matchings in two infinite families of bounded-degree graphs built by chaining copies of a fixed base unit: the open chain and the cyclic chain.

3. Biserka Kolarec (Agronomski fakultet, Zagreb): Directed sequential arrangements of families of circles

Sažetak: Directed sequential arrangements of circles in the plane belonging to two distinct families are considered. In both cases, circle radii are given by r_n = 1/a_n for a specified sequence (a_n), n≥0 . We analyze the sequence of circle centers and investigate its convergence in terms of properties of the sequence a_n. We also present the interesting case of orthogonal family of satellite unit circles in which the circle centers are concyclic.

4. Tomislav Došlić (Građevinski fakultet, Zagreb): Counting Dewar structures in hexagonal chains

Sažetak: We present explicit formulas for the number of Dewar structures in some classes of hexagonal chains.

Pozivaju se članovi Seminara i svi ostali zainteresirani da prisustvuju ovim predavanjima.

Tajnik seminara,

Goran Igaly