TY - JOUR AU - Pongrácz, András TI - Extremal solutions of an inequality concerning supports of permutation groups and punctured Hadamard codes JF - PUBLICACIONS MATEMATIQUES J2 - PUBL MAT VL - 66 PY - 2022 IS - 1 SP - 57 EP - 75 PG - 19 SN - 0214-1493 DO - 10.5565/PUBLMAT6612202 UR - https://m2.mtmt.hu/api/publication/32171117 ID - 32171117 LA - English DB - MTMT ER - TY - JOUR AU - Pongrácz, András AU - Vincze, Csaba TI - On the reconstruction of the center of a projection by distances and incidence relations JF - JOURNAL OF MATHEMATICAL IMAGING AND VISION J2 - J MATH IMAGING VIS VL - 63 PY - 2021 IS - 4 SP - 443 EP - 456 PG - 14 SN - 0924-9907 DO - 10.1007/s10851-020-00999-w UR - https://m2.mtmt.hu/api/publication/31669419 ID - 31669419 AB - Up to an orientation-preserving symmetry, photographic images are produced by a central projection of a restricted area in the space into the image plane. To obtain reliable information about physical objects and the environment through the process of recording is the basic problem of photogrammetry. We present a reconstruction process based on distances from the center of projection and incidence relations among the points to be projected. For any triplet of collinear points in the space, we construct a surface of revolution containing the center of the projection. It is a generalized conic that can be represented as an algebraic surface. The rotational symmetry allows us to restrict the investigations to the defining polynomial of the profile curve in the image plane. An equivalent condition for the boundedness is given in terms of the input parameters, and it is shown that the defining polynomial of the profile curve is irreducible. LA - English DB - MTMT ER - TY - JOUR AU - Manuel, Bodirsky AU - Michael, Pinsker AU - Pongrácz, András TI - Projective clone homomorphisms JF - JOURNAL OF SYMBOLIC LOGIC J2 - J SYMBOLIC LOGIC VL - 86 PY - 2021 IS - 1 SP - 148 EP - 161 PG - 13 SN - 0022-4812 DO - 10.1017/jsl.2019.23 UR - https://m2.mtmt.hu/api/publication/3188105 ID - 3188105 AB - It is known that a countable -categorical structure interprets all finite structures primitively positively if and only if its polymorphism clone maps to the clone of projections on a two-element set via a continuous clone homomorphism. We investigate the relationship between the existence of a clone homomorphism to the projection clone, and the existence of such a homomorphism which is continuous and thus meets the above criterion. LA - English DB - MTMT ER - TY - JOUR AU - Pongrácz, András TI - Binary linear codes with near-extremal maximum distance JF - SIAM JOURNAL ON DISCRETE MATHEMATICS J2 - SIAM J DISCRETE MATH VL - 34 PY - 2020 IS - 4 SP - 2300 EP - 2317 PG - 18 SN - 0895-4801 DO - 10.1137/19M1288498 UR - https://m2.mtmt.hu/api/publication/31618390 ID - 31618390 LA - English DB - MTMT ER - TY - JOUR AU - Pongrácz, András TI - Discordant voting protocols for cyclically linked agents JF - ELECTRONIC JOURNAL OF COMBINATORICS J2 - ELECTRON J COMB VL - 27 PY - 2020 IS - 1 PG - 14 SN - 1097-1440 DO - 10.37236/8578 UR - https://m2.mtmt.hu/api/publication/31618382 ID - 31618382 AB - Voting protocols, such as the push and the pull protocol, model the behavior of people during an election. These processes have been studied in distributed computing in peer-to-peer networks, and to describe how viruses or rumors spread in a community. We determine the asymptotic behavior of the runtime of discordant linear protocols on the cycle graph and the probability for each consensus to win. LA - English DB - MTMT ER - TY - JOUR AU - Kátai-Urbán, Kamilla AU - Pongrácz, András AU - Szabó, Csaba TI - The fine- and generative spectra of varieties of monounary algebras JF - ALGEBRA UNIVERSALIS J2 - ALGEBR UNIV VL - 80 PY - 2019 IS - 2 PG - 18 SN - 0002-5240 DO - 10.1007/s00012-019-0596-2 UR - https://m2.mtmt.hu/api/publication/3421943 ID - 3421943 N1 - Cited By :1 Export Date: 1 June 2023 Correspondence Address: Pongrácz, A.; Department of Algebra and Number Theory, Egyetem Square 1, Hungary; email: pongracz.andras@science.unideb.hu LA - English DB - MTMT ER - TY - JOUR AU - Bodirsky, M AU - Martin, B AU - Pinsker, M AU - Pongrácz, András TI - Constraint satisfaction problems for reducts of homogeneous graphs JF - SIAM JOURNAL ON COMPUTING J2 - SIAM J COMPUT VL - 48 PY - 2019 IS - 4 SP - 1224 EP - 1264 PG - 41 SN - 0097-5397 DO - 10.1137/16M1082974 UR - https://m2.mtmt.hu/api/publication/3421941 ID - 3421941 AB - For n >= 3, let (H-n, E) denote the nth Henson graph, i.e., the unique countable homogeneous graph with exactly those finite graphs as induced subgraphs that do not embed the complete graph on n vertices. We show that for all structures Gamma with domain H-n whose relations are first-order definable in (H-n, E) the constraint satisfaction problem for F either is in P or is NP-complete. We moreover show a similar complexity dichotomy for all structures whose relations are first-order definable in a homogeneous graph whose reflexive closure is an equivalence relation. Together with earlier results, in particular for the random graph, this completes the complexity classification of constraint satisfaction problems of structures first-order definable in countably infinite homogeneous graphs: all such problems are either in P or NP-complete. LA - English DB - MTMT ER - TY - CHAP AU - Pongrácz, András TI - Discordant voting Protocols for cyclically linked agents T2 - Proceedings of the World Congress on Engineering 2018 Vol I PB - Newswood Limited CY - Hong Kong SN - 9789881404794 PY - 2018 SP - 165 EP - 168 PG - 4 UR - https://m2.mtmt.hu/api/publication/3421953 ID - 3421953 LA - English DB - MTMT ER - TY - JOUR AU - Manuel, Bodirsky AU - David, Bradley-Williams AU - Michael, Pinsker AU - Pongrácz, András TI - The universal homogeneous binary tree JF - JOURNAL OF LOGIC AND COMPUTATION J2 - J LOGIC COMPUT VL - 28 PY - 2018 IS - 1 SP - 133 EP - 163 PG - 31 SN - 0955-792X DO - 10.1093/logcom/exx043 UR - https://m2.mtmt.hu/api/publication/3339274 ID - 3339274 N1 - Institut für Algebra, TU Dresden, Germany Mathematisches Institut der Heinrich-Heine-Universität, Universitätsstr 1, Germany Institut für Diskrete Mathematik und Geometrie, FG Algebra, Austria Department of Algebra, Charles University, Czech Republic Department of Algebra and Number Theory, University of Debrecen, Hungary Cited By :5 Export Date: 15 June 2022 CODEN: JLCOE LA - English DB - MTMT ER - TY - JOUR AU - Barnaby, Martin AU - Pongrácz, András AU - Michal, Wrona TI - The complexity of counting quantifiers on equality languages JF - THEORETICAL COMPUTER SCIENCE J2 - THEOR COMPUT SCI VL - 670 PY - 2017 SP - 56 EP - 67 PG - 12 SN - 0304-3975 DO - 10.1016/j.tcs.2017.01.022 UR - https://m2.mtmt.hu/api/publication/3183038 ID - 3183038 LA - English DB - MTMT ER -