1. Extremal totally regular mixed graphs and partially oriented incidence graphs of projective and biaffine planesTatiana Bagin Jajcay, Robert Jajcay, György Kiss, István Porupsánszki, 2025, original scientific article Abstract: An (r, z; g)-mixed graph is a graph containing both edges and darts satisfying the regularity property that each vertex of the graph is incident to r edges, z ingoing and z outgoing darts (called total regularity), and being of oriented girth g, i.e., containing an oriented cycle of length g, and no shorter oriented cycles. The problem addressed in this paper is analogous to the Cage Problem and calls for determining the orders of the smallest totally regular (r, z; g)-mixed graphs. We derive several upper and lower bounds on the orders of such minimal graphs, study the relations between these extremal graphs and their non-oriented or digraphical counterparts, and focus on properties of totally regular mixed graphs obtained by replacing some of the edges of the incidence graphs of projective and biaffine planes by darts. We also introduce two constructions based on introducing additional edges or darts into induced subgraphs of these incidence graphs.
Keywords: totally regular mixed graph, girth, projective plane, biaffine plane
Published in RUP: 04.06.2026; Views: 261; Downloads: 8
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2. Partial geometries with regular automorphism groups : master’s thesisAdisa Hodžić, 2024, master's thesis Keywords: (near-) linear space, projective plane, affine plane, partial geometry, generalized quadrangle, strongly regular graph, partial difference set, automorphism group
Published in RUP: 25.12.2024; Views: 2495; Downloads: 59
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4. Combinatorial configurations, quasiline arrangements, and systems of curves on surfacesJürgen Bokowski, Jurij Kovič, Tomaž Pisanski, Arjana Žitnik, 2018, original scientific article Keywords: pseudoline arrangement, quasiline arrangement, projective plane, incidence structure, combinatorial configuration, topological configuration, geometric configuration, sweep, wiring diagram, allowable sequence of permutations, maps on surfaces
Published in RUP: 03.01.2022; Views: 2583; Downloads: 32
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