English

About F\"uredi's conjecture

Combinatorics 2024-06-11 v1

Abstract

Let tt be a non-negative integer and \mbox{\cal P}=\{(A_i,B_i)\}_{1\leq i\leq m} be a set-pair family satisfying AiBit|A_i \cap B_i|\leq t for 1im1\leq i \leq m. \mbox{\cal P} is called strong Bollob\'as tt-system, if AiBj>t|A_i\cap B_j|>t for all 1ijm1\leq i\neq j \leq m. F\"uredi conjectured the following nice generalization of Bollob\'as' Theorem: Let tt be a non-negative integer. Let \mbox{\cal P}=\{(A_i,B_i)\}_{1\leq i\leq m} be a strong Bollob\'as tt-system. Then i=1m1(Ai+Bi2tAit)1. \sum_{i=1}^m \frac{1}{{|A_i|+|B_i|-2t \choose |A_i|-t}}\leq 1. We confirmed the following special case of F\"uredi's conjecture along with some more results of similar flavor. Let tt be a non-negative integer. Let \mbox{\cal P}=\{(A_i,B_i)\}_{1\leq i\leq m} denote a strong Bollob\'as tt-system. Define ai:=Aia_i:=|A_i| and bi:=Bib_i:=|B_i| for each ii. Assume that there exists a positive integer NN such that ai+bi=Na_i+b_i=N for each ii. Then i=1m1(ai+bi2tait)1. \sum_{i=1}^m \frac{1}{{a_i+b_i-2t \choose a_i-t}}\leq 1.

Keywords

Cite

@article{arxiv.2406.05841,
  title  = {About F\"uredi's conjecture},
  author = {Gábor Hegedüs},
  journal= {arXiv preprint arXiv:2406.05841},
  year   = {2024}
}
R2 v1 2026-06-28T16:58:51.812Z