The Erdős–Ko–Rado-type conjecture for L-intersecting families

Let 0<skn0<s\leq k\leq n be positive integers. Let L={1,,s}L=\{\ell_1,\ldots,\ell_s\} be a set of ss positive integers such that 0<1<<s0<\ell_1<\cdots<\ell_s. Suppose that n>k2k+1n>k^2-k+1. Let F={F1,,Fm}\mathcal F=\{F_1,\ldots,F_m\} be an LL-intersecting, kk-uniform family of subsets of [n][n], meaning that FiFjL|F_i\cap F_j|\in L for every distinct Fi,FjFF_i,F_j\in\mathcal F. The Erdős–Ko–Rado-type conjecture for LL-intersecting families. Then

m(n1s).m\leq {n-\ell_1\choose s}.

Moreover, if

F=(n1s),|\mathcal F|={n-\ell_1\choose s},

then there exists a set T([n]1)T\in {[n]\choose \ell_1} such that TFT\subseteq F for every FFF\in\mathcal F. This conjecture extends the preceding bound and its equality characterization from the proven range to the stated condition n>k2k+1n>k^2-k+1; the projective-plane example motivating it shows why the threshold is natural. Its resolution is not indicated in the supplied text.

Sources & referencesView supporting material

Primary source

Gábor Hegedüs, “A generalization of the Erdős-Ko-Rado Theorem”, arXiv:1512.05531 (2015).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.