Maximal 3-Wise Intersecting Families
Maximal 3-Wise Intersecting Families
复制标题
最大三向相交族
作者:
J. Balogh;Ce Chen;Kevin Hendrey;Ben D. Lund;Haoran Luo;C. Tompkins;T. Tran
A family Fdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$${mathcal {F}}$$end{document} on ground set [n]:={1,2,…,n}documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$[n]:={1,2,ldots , n}$$end{document} is maximalk-wise intersecting if every collection of at most k sets in Fdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$${mathcal {F}}$$end{document} has non-empty intersection, and no other set can be added to Fdocumentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$${mathcal {F}}$$end{document} while maintaining this property. In 1974, Erdős and Kleitman asked for the minimum size of a maximal k-wise intersecting family. We answer their question for k=3documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$k=3$$end{document} and sufficiently large n. We show that the unique minimum family is obtained by partitioning the ground set [n] into two sets A and B with almost equal sizes and taking the family consisting of all the proper supersets of A and of B.
DOI:
10.5070/c62257877
发表时间:
2022
期刊:
Combinatorial Theory
影响因子:
--
作者:
Janzer B
通讯作者:
Janzer B
DOI:
10.1016/j.jctb.2015.05.009
发表时间:
2015
期刊:
J. Comb. Theory, Ser. B
影响因子:
--
作者:
N. Alon;S. Das;R. Glebov;B. Sudakov
通讯作者:
B. Sudakov