Abstract
Increasing attention is being paid to the study of families of subsets of an n-set that contain no subposet P. Especially, we are interested in such families of maximum size given P and n. For certain P this problem is solved for general n, while for other P it is extremely challenging to find even an approximate solution for large n. It is conjectured that for any P, the maximum size is asymptotic to a constant times \(\binom{n}{\lfloor \frac{n} {2} \rfloor }\), where the constant is a certain integer depending on P. This survey has two purposes. First, we want to bring this exciting line of research to the attention of a wider audience. Second, we want to make experts aware of the broad range of recent progress in the area.
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Notes
- 1.
After this survey went to press, we learned that Arès Méroueh announced a proof of the conjecture (ArXiv:1506.07056).
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Acknowledgements
Research of Jerrold R. Griggs was supported in part by a grant from the Simons Foundation (#282896 to Jerrold Griggs) and by a long-term visiting position at the IMA, University of Minnesota.
Wei-Tian Li was supported by Ministry of Science and Technology (No. 103-2115-M-005 -003 -MY2).
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Griggs, J.R., Li, WT. (2016). Progress on poset-free families of subsets. In: Beveridge, A., Griggs, J., Hogben, L., Musiker, G., Tetali, P. (eds) Recent Trends in Combinatorics. The IMA Volumes in Mathematics and its Applications, vol 159. Springer, Cham. https://doi.org/10.1007/978-3-319-24298-9_14
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