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Title Dual digraphs of finite semidistributive lattices Author info Andrew Craig ... [et al.] Author Craig Andrew (34%)
Co-authors Haviar Miroslav 1965- (33%) UMBFP10 - Katedra matematiky
São João José (33%)
Source document Cubo : a mathematical journal. Vol. 24, no. 3 (2022), pp. 369-392. - Temuco : Department of mathematics and statistics of the Universidad de La Frontera, 2021 Keywords grafové algoritmy algebraické štruktúry - algebraic structures matematika - mathematics Form. Descr. články - journal articles Language English Country Chile Annotation Dual digraphs of finite join-semidistributive lattices, meet-semidistributive lattices and semidistributive lattices are characterised. The vertices of the dual digraphs are maximal disjoint filter-ideal pairs of the lattice. The approach used here combines representations of arbitrary lattices due to Urquhart (1978) and Ploščcica (1995). The duals of finite lattices are mainly viewed as TiRS digraphs as they were presented and studied in Craig–Gouveia–Haviar (2015 and 2022). When appropriate, Urquhart’s two quasi-orders on the vertices of the dual digraph are also employed. Transitive vertices are introduced and their role in the domination theory of the digraphs is studied. In particular, finite lattices with the property that in their dual TiRS digraphs the transitive vertices form a dominating set (respectively, an in-dominating set) are characterised. A characterisation of both finite meet- and join-semidistributive lattices is provided via minimal closure systems on the set of vertices of their dual digraphs. URL Link na plný text Public work category ADM No. of Archival Copy 52754 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika Title Cubo Subtitle a mathematical journal Issue data Temuco : Department of mathematics and statistics of the Universidad de La Frontera , 2021 ISSN 0716-7776 (print)0719-0646 (online) Form. Descr. časopisy - journals, elektronické časopisy - electronic journals Year, No. Vol. 24 no. 3 (2022) Language English Country Chile URL Link na zdrojový dokument Public work category GII Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References - PERIODIKÁ - Súborný záznam periodika (1) - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika ARTICLES 2022: Dual digraphs of finite semidistributive lattices Title Cubo Subtitle a mathematical journal Issue data Temuco : Department of mathematics and statistics of the Universidad de La Frontera , 2021 ISSN 0716-7776 (print)0719-0646 (online) Form. Descr. časopisy - journals, elektronické časopisy - electronic journals Year, No. Vol. 23 no. 2 (2021) Language English Country Chile URL Link na zdrojový dokument Public work category GII Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References - PERIODIKÁ - Súborný záznam periodika (1) - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika ARTICLES 2021: A new class of graceful graphs: k-enriched fan graphs and their characterisations Title A new class of graceful graphs: k-enriched fan graphs and their characterisations Author info Miroslav Haviar, Samuel Kurtulík Author Haviar Miroslav 1965- (50%) UMBFP10 - Katedra matematiky
Co-authors Kurtulík Samuel (50%)
Source document Cubo : a mathematical journal. Vol. 23, č. 2 (2021), pp. 313-331. - Temuco : Department of mathematics and statistics of the Universidad de La Frontera, 2021 Keywords grafy - charts - graphs graciózne ohodnotenie grafov - graceful labelling of graphs grafové šachovnice - graph chessboards postupnosť Form. Descr. články - journal articles Language English Country Chile Annotation The Graceful Tree Conjecture stated by Rosa in the mid 1960s says that every tree can be gracefully labelled. It is one of the best known open problems in Graph Theory. The conjecture has caused a great interest in the study of gracefulness of simple graphs and has led to many new contributions to the list of graceful graphs. However, it has to be acknowledged that not much is known about the structure of graceful graphs after 55 years. Our paper adds an infinite family of classes of graceful graphs to the list of known simple graceful graphs. We introduce classes of k-enriched fan graphs kF_n for all integers k, n ≥ 2 and we prove that these graphs are graceful. Moreover, we provide characterizations of the k-enriched fan graphs kF_n among all simple graphs via Sheppard's labelling sequences introduced in the 1970s, as well as via labelling relations and graph chessboards. These last approaches are new tools for the study of graceful graphs introduced by Haviar and Ivaška in 2015. The labelling relations are closely related to Sheppard's labelling sequences while the graph chessboards provide a nice visualization of graceful labellings. We close our paper with an open problem concerning another infinite family of extended fan graphs. URL Link na zdrojový dokument Link na plný text Public work category ADM No. of Archival Copy 50548 Catal.org. BB301 - Univerzitná knižnica Univerzity Mateja Bela v Banskej Bystrici Database xpca - PUBLIKAČNÁ ČINNOSŤ References PERIODIKÁ-Súborný záznam periodika