Abstract
The main question in the on-line chain partitioning problem is to decide whether there exists an on-line algorithm that partitions posets of width at most w into polynomial number of chains — see Trotter’s chapter Partially ordered sets in the Handbook of Combinatorics. So far the best known on-line algorithm of Kierstead used at most (5w − 1)/4 chains; on the other hand Szemerédi proved that any on-line algorithm requires at least \(\left( {\begin{array}{*{20}c} {w + 1} \\ 2 \\ \end{array} } \right)\) chains. These results were obtained in the early eighties and since then no progress in the general case has been done.
We provide an on-line algorithm that partitions posets of width w into at most w 13logw chains. This yields the first subexponential upper bound for the on-line chain partitioning problem.
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References
P. Baier, B. Bosek and P. Micek: On-line chain partitioning of up-growing interval orders, Order 24 (2007), 1–13.
B. Bosek: On-line chain partitioning approach to scheduling, Ph.D. thesis, Jagiellonian University, 2008.
B. Bosek, S. Felsner, K. Kloch, T. Krawczyk, G. Matecki and P. Micek: On-line chain partitions of orders: survey, Order 29 (2012), 49–73.
B. Bosek, H. A. Kierstead, T. Krawczyk, G. Matecki and M. E. Smith: Regular posets and on-line chain partitioning, manuscript, 2013.
B. Bosek and T. Krawczyk: On-line chain partitioning of 2-dimensional orders, unpublished result, 2010.
B. Bosek, T. Krawczyk and G. Matecki: First—fit coloring of incomparability graphs, SIAM J. Discrete Math. 27 (2013), 126–140.
B. Bosek, T. Krawczyk and E. Szczypka: First—fit algorithm for the on-line chain partitioning problem, SIAM J. Discrete Math. 23 (2010), 1992–1999.
P. Broniek: On-line chain partitioning as a model for real-time scheduling, in: Proceedings of the Second Workshop on Computational Logic and Applications (CLA 2004) (Amsterdam), Electron. Notes Theor. Comput. Sci. 140, Elsevier, 2005, 15–29 (electronic).
M. Chrobak and M. ślusarek: On some packing problem related to dynamic storage allocation, RAIRO Inform. Théor. Appl. 22 (1988), 487–499.
V. DujmoviĆ, G. Joret and D. R. Wood: An Improved Bound for First-Fit on Posets Without Two Long Incomparable Chains, SIAM J. Discrete Math. 26 (2012), 1068–1075.
S. Felsner: On-line chain partitions of orders, Theoret. Comput. Sci. 175 (1997), 283–292.
S. Felsner, K. Kloch, G. Matecki and P. Micek: On-line Chain Partitions of Up-growing Semi-orders, Order 30 (2013), 85–101.
G. Joret and K. Milans: First—fit is linear on posets excluding two long incomparable chains, Order 28 (2011), 455–464.
H. A. Kierstead: An e ective version of Dilworth’s theorem, Trans. Amer. Math. Soc. 268 (1981), 63–77.
H. A. Kierstead: Recursive ordered sets, Combinatorics and ordered sets (Arcata, Calif., 1985), Contemp. Math. 57, Amer. Math. Soc., Providence, RI, 1986, 75–102.
H. A. Kierstead, G. F. McNulty and W. T. Trotter: A theory of recursive dimension for ordered sets, Order 1 (1984), 67–82.
H. A. Kierstead and M. E. Smith: On First—fit coloring of ladder-free posets, European J. Combin. 34 (2013), 474–489.
H. A. Kierstead and W. T. Trotter: An extremal problem in recursive combi-natorics, in: Proceedings of the Twelfth Southeastern Conference on Combinatorics, Graph Theory and Computing, Vol. II (Baton Rouge, La., 1981), 33, 1981, 143–153.
P. Micek: On-line chain partitioning of semi-orders, Ph.D. thesis, Jagiellonian University, 2008.
W. T. Trotter: Partially ordered sets, Handbook of combinatorics, 1, Elsevier, Amsterdam, 1995, 433–480.
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This work was supported by Polish Ministry of Science and Higher Education Grant (MNiSW) No. N206492338.
Extended abstract of this article has been published in proceedings of 51th Annual IEEE Symposium on Foundations of Computer Science, FOCS 2010.
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Bosek, B., Krawczyk, T. A subexponential upper bound for the on-line chain partitioning problem. Combinatorica 35, 1–38 (2015). https://doi.org/10.1007/s00493-014-2908-7
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DOI: https://doi.org/10.1007/s00493-014-2908-7