arXiv Code and data search.c 221000.dat plot5.ggb – Geogebra notebook geo5.sh – awk one-liner to format array to input parameters to Geogebra Errata Every time I wrote I should have written . This will be corrected in the final version. The pigeonhole upper bound is perhaps better written , since it arises as , where …
Category: Bibliography
The Namer-Claimer game, part 2
Discrete Mathematics, Volume 344, Issue 3, March 2021, 112256 https://doi.org/10.1016/j.disc.2020.112256 arXiv I’ve previously written about the Namer-Claimer game. I can now prove that the length of the game is with optimal play from each side, matching the greedy lower bound. The upper bound makes use of randomness, but in a very controlled way. Analysing a truly …
Minimalist designs
Ben Barber, Stefan Glock, Daniela Kühn, Allan Lo, Richard Montgomery, Deryk Osthus Random Struct Alg. 2020; 57: 47– 63. https://doi.org/10.1002/rsa.20915 In Edge decompositions of graphs with high minimum degree, Daniela Kühn, Allan Lo, Deryk Osthus and I proved that the edge sets of sufficiently dense graphs satisfying necessary divisibility conditions could be partitioned into copies of …
Clique decompositions of multipartite graphs and completion of Latin squares
Ben Barber, Daniela Kühn, Allan Lo, Deryk Osthus and Amelia Taylor, Journal of Combinatorial Theory, Series A, Volume 151, October 2017, Pages 146–201 PDF A Latin square of order is an grid of cells, each of which contains one of distinct symbols, such that no symbol appears twice in any row or column. There is a natural …
Partition regularity and other combinatorial problems
This is the imaginative title of my PhD thesis. It contains four unrelated pieces of work. (I was warned off using this phrasing in the thesis itself, where the chapters are instead described as “self-contained”.) The first and most substantial concerns partition regularity. It is a coherent presentation of all of the material from Partition …
Fractional clique decompositions of dense graphs and hypergraphs
Ben Barber, Daniela Kühn, Allan Lo, Richard Montgomery and Deryk Osthus, Journal of Combinatorial Theory, Series B, Volume 127, November 2017, Pages 148–186 PDF Together with Daniela Kühn, Allan Lo and Deryk Osthus I proved that for every graph there is a constant such that every “-divisible” graph on vertices with minimum degree at least has an …
Edge-decompositions of graphs with high minimum degree
Ben Barber, Daniela Kühn, Allan Lo and Deryk Osthus, Advances in Mathematics, Volume 288, 22 January 2016, Pages 337–385 PDF When can the edge set of a graph be partitioned into triangles? Two obvious necessary conditions are that the total number of edges is divisible by 3 and the degree of every vertex is even. We …
Distinguishing subgroups of the rationals by their Ramsey properties
Ben Barber, , Neil Hindman, Imre Leader and Dona Strauss, Journal of Combinatorial Theory, Series A, Volume 129, January 2015, Pages 93–104 PDF In Partition regularity in the rationals we (Barber, Hindman and Leader) showed that there are systems of equations that are partition regular over but not over . Here we show that this separation is …
Partition regularity without the columns property
Ben Barber, Neil Hindman, Imre Leader and Dona Strauss, Proc. Amer. Math. Soc. 143 (2015), 3387-3399 PDF Rado’s theorem states that a finite matrix is partition regular if and only if it has the “columns property”. It is easy to write down infinite matrices with the columns property that are not partition regular, but all known …