Search results
Title On a representation of the automorphism group of a graph in a unimodular group Author info István Estélyi ... [et al.] Author Estélyi István (5%)
Co-authors Karabáš Ján 1977- (40%) UMBFP05 - Katedra informatiky
Nedela Roman 1960- (50%)
Mednykh Alexander 1953- (5%)
Source document Discrete Mathematics. Vol. 344, no. 12 (2021), pp. [1-4]. - Amsterdam : Elsevier B.V., 2021 Keywords matematika - mathematics grafy - charts - graphs Form. Descr. články Language English Country Netherlands Annotation We investigate a representation of the automorphism group of a connected graph X in the group of unimodular matrices U(β) of dimension β, where β is the Betti number of graph X. We classify the graphs for which the automorphism group does not embed into U(β). It follows that if X has no pendant vertices and X is not a simple cycle, then the representation is faithful and Aut X acts faithfully on H_1(X,Z). The latter statement can be viewed as a discrete analogue of a classical Hurwitz’s theorem on Riemann surfaces of genera greater than one. URL Link na plný text Public work category ADM No. of Archival Copy 50763 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika 
article
Title On discrete versions of two Accola´s theorems about automorphism groups of Riemann surfaces Author info Maxim Limonov, Roman Nedela, Alexander Mednykh Author Limonov Maksim (33%)
Co-authors Nedela Roman 1960- (34%) UMBFP05 - Katedra informatiky
Mednykh Alexander 1953- (33%)
Source document Analysis and Mathematical Physics. Vol. 7, no. 3 (2017), pp. 233-243. - Cham : Springer Nature Switzerland AG, 2017 Keywords Riemanove plochy - Riemann surfaces grafy - charts - graphs automorphism groups hyperelliptic graphs hyperelliptic involutions harmonic maps Language English Country Switzerland systematics 51 Annotation In this paper we give a few discrete versions of Robert Accola’s results on Riemann surfaces with automorphism groups admitting partitions. As a consequence, we establish a condition for γ-hyperelliptic involution on a graph to be unique. Also we construct an infinite family of graphs with more than one γ-hyperelliptic involution. Public work category ADC No. of Archival Copy 41751 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika 
unrecognised
Title Recent progress in enumeration of hypermaps Author info A. Mednykh, R. Nedela Author Mednykh Alexander 1953- (50%) UMBFP10 - Katedra matematiky
Co-authors Nedela Roman 1960- (50%) UMBFP12 - Inštitút matematiky a informatiky
Source document Zapiski nauchnykh seminarov POMI. online, vol. 446 (2016), pp. 139-164. - St. Petersburg : POMI, 2016 Keywords kombinatorická enumerácia - combinatorial enumeration surfaces orbifold rooted hypermap unrooted hypermaps Fuchsian groups Language English Country Russian Federation systematics 51 URL http://www.mathnet.ru/php/archive.phtml?wshow=paper&jrnid=znsl&paperid=6287&option_lang=rus Public work category ADE No. of Archival Copy 36959 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ article
Title Counting hypermaps by Egorychev’s method Author info Alexander Mednykh, Roman Nedela Author Mednykh Alexander 1953- (50%) UMBFP10 - Katedra matematiky
Co-authors Nedela Roman 1960- (50%) UMBFP10 - Katedra matematiky
Source document Analysis and Mathematical Physics. Vol. 6, no. 3 (2016), pp. 301-314. - Cham : Springer Nature Switzerland AG, 2016 Keywords Fuchsian groups hypermapy hypermaps matematika - mathematics Language English Country Germany systematics 51 Annotation © 2015, Springer Basel.The aim of this paper is to find explicit formulae for the number of rooted hypermaps with a given number of darts on an orientable surface of genus g≤ 3. Such formulae were obtained earlier for g= 0 and g= 1 by Walsh and Arquès respectively. We first employ the Egorychev’s method of counting combinatorial sums to obtain a new version of the Arquès formula for genus g= 1. Then we apply the same approach to get new results for genus g= 2 , 3. We could do it due to recent results by Giorgetti, Walsh, and Kazarian, Zograf who derived two different, but equivalent, forms of the generating functions for the number of hypermaps of genus two and three. Public work category ADC No. of Archival Copy 36932 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika unrecognised
Title Harmonic morphisms of graphs and the Riemann-Hurwitz theorem Author info A. D. Mednykh, Roman Nedela Author Mednykh Alexander 1953- (50%)
Co-authors Nedela Roman 1960- (50%) UMBFP05 - Katedra informatiky
Source document Doklady Mathematics. Vol. 93, no. 1 (2016), pp. 23-26. - Moscow : Pleiades Publishing, 2016 Keywords Riemannova geometria - Riemannian geometry grafy - charts - graphs Language English Country United States of America systematics 51 Public work category ADC No. of Archival Copy 36695 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika unrecognised
Title Harmonic morphisms of graphs Document part Part I. Graph coverings Author info Alexander D. Mednykh, Roman Nedela Author Mednykh Alexander 1953-
Co-authors Nedela Roman 1960-
Issue data Banská Bystrica : Vydavateľstvo Univerzity Mateja Bela - Belianum, Fakulta prírodných vied , 2015. - vi; 82 s. : obr., tab., 25 cm Issue 1st ed. ISBN 978-80-557-1065-5 Note Bibliografia s. 75-80. Register Keywords teória grafov - graph theory matematika - mathematics Language English Country Slovak Republic systematics 519.17 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xkni - BOOKS Copy count 5, currently available 4, at library only 1 
book
Call number Location Sublocation Umiestnenie Info 355027 Univerzita Mateja Bela Universal reading room In-Library Use Only 355028 Univerzita Mateja Bela Department of absent lending 355029 Univerzita Mateja Bela Department of absent lending 355030 Univerzita Mateja Bela Department of absent lending 355031 Univerzita Mateja Bela Department of absent lending Title Graphs with automorphism groups admitting partitions Author info M. Limonov, R. Nedela, A. Mednykh Author Limonov Maksim (34%)
Co-authors Nedela Roman 1960- (33%) UMBFP05 - Katedra informatiky
Mednykh Alexander 1953- (33%)
Source document Siberian electronic mathematical reports. online, no. 12 (2015), pp. 723-731. - Novosibirsk : Sobolev Institue of Mathematics, 2015 Keywords grafy - charts - graphs matematika - mathematics Language English Country Russian Federation systematics 51 URL http://semr.math.nsc.ru Public work category ADE No. of Archival Copy 35359 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ unrecognised
Title Harmonic morphism of graphs Document part Part 1. Graph coverings Author info Alexander Mednykh, Roman Nedela Author Mednykh Alexander 1953- (50%) UMBFP10 - Katedra matematiky
Co-authors Nedela Roman 1960- (50%) UMBFP05 - Katedra informatiky
Issue data Banská Bystrica : Vydavateľstvo Univerzity Mateja Bela - Belianum , 2015. - 80 s. Issue 1. vyd. ISBN 978-80-557-1065-5 Keywords matematika - mathematics grafy - charts - graphs Language English Country Slovak Republic systematics 51 Public work category BAB No. of Archival Copy 35516 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ 
book
Title O nekotorych obobščenijach teoremy Gurvica dľa grupp, dejstvujuščich na grafe Author info A. Mednykh, I. A. Mednykh, R. Nedela Author Mednykh Alexander 1953- (20%)
Co-authors Mednykh Iľja Aleksandrovič (10%)
Nedela Roman 1960- (70%) UMBFP10 - Katedra matematiky
Source document Doklady Akademii Nauk. Roč. 460, č. 5 (2015), s. 1-8. - Moskva : Prezídium Ruskej akadémie vied, 2015 Language Russian Country Russian Federation URL http://www.maik.ru/cgi-perl/journal.pl?lang=rus&name=dan&mode=print Public work category ADE No. of Archival Copy 32961 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ unrecognised
Title On Wiman's theorem for graphs Author info Alexander Mednykh, Ilya Mednykh Author Mednykh Alexander 1953- (75%) UMBFP10 - Katedra matematiky
Co-authors Mednykh Ilya (25%)
Source document Discrete Mathematics. Vol. 338, no. 10 special issue (2015), pp. 1793-1800. - Amsterdam : Elsevier B.V., 2015 ; Czech-Slovak international symposium on graph theory, combinatorics, algorithms and applications medzinárodné sympózium Keywords matematika - mathematics grafy - charts - graphs Language English Country Netherlands systematics 51 Annotation © 2015 Elsevier B.V.Abstract The aim of the paper is to find discrete versions of the Wiman theorem which states that the maximum possible order of an automorphism of a Riemann surface of genus g≥2 is 4g+2. The role of a Riemann surface in this paper is played by a finite connected graph. The genus of a graph is defined as the rank of its homology group. Let ZinfN/inf be a cyclic group acting freely on the set of directed edges of a graph X of genus g≥2. We prove that N≤2g+2. The upper bound N=2g+2 is attained for any even g. In this case, the signature of the orbifold X/ZinfN/inf is (0;2,g+1), that is X/ZinfN/inf is a tree with two branch points of order 2 and g+1 respectively. Moreover, if N<2g+2, then N≤2g. The upper bound N=2g is attained for any g≥2. The latter takes a place when the signature of the orbifold X/ZinfN/inf is (0;2,2g). Public work category AFC No. of Archival Copy 36748 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika unrecognised
