Butterfly supersaturation conjecture up to the packing number

Let [n]={1,,n}[n]=\{1,\ldots,n\}, let 2[n]2^{[n]} denote the family of all subsets of [n][n], and let Σ(n,2)\Sigma(n,2) be the size of the two middle levels of the Boolean lattice. Write K(n,n/2+1)K(n,\lceil n/2\rceil+1) for the largest family of (n/2+1)(\lceil n/2\rceil+1)-element sets whose distinct members have intersection at most n/21\lceil n/2\rceil-1, and let f(n)f(n) denote the number of butterflies containing one additional set above the two middle levels.

Butterfly supersaturation conjecture. Let E=E(n)K(n,n/2+1)E=E(n)\le K(n,\lceil n/2\rceil+1). If nn is large enough, then the minimum number of butterflies a family F2[n]\mathcal F\subset 2^{[n]} of size Σ(n,2)+E\Sigma(n,2)+E must contain is Ef(n)Ef(n).

The claim predicts the exact supersaturation threshold for families just larger than the two middle levels, within the range allowed by the packing parameter K(n,n/2+1)K(n,\lceil n/2\rceil+1). The paper explains that its methods do not reach this range even asymptotically, so the conjecture remains open.

Sources & referencesView supporting material

Primary source

Balazs Patkos, “Supersaturation and stability for forbidden subposet problems”, arXiv:1406.1887 (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.