Showing 2026Show all
4 papers · 1 filter
math.CO2026
Proving the optimality of the product construction for the intersection--union problem
Fan Chang, Peter Frankl, Jian Wang
Let be the largest size of a family of subsets of whose members pairwise intersect in at least vertices and omit at least common vertices. We prove that a…
math.CO2026
Stability for Helly-type and triangle-free families
Peter Frankl, Jian Wang
We consider -graphs, , . A -graph is called intersecting if any two of its edges have non-empty intersection. It is called a star…
math.CO2026
A product version of the Hilton-Milner Theorem II
Peter Frankl, Jian Wang
Two families of -subsets of are called {\it non-trivial cross-intersecting} if for all $F\in \mathcal{F}, G\…
math.CO2026
The exact Erdős-Ko-Rado Theorem for 3-wise -intersecting uniform families
Peter Frankl, Jian Wang
One of the central problems in extremal set theory is the determination of the maximum size of an -wise -intersecting -graph on vertices. For after decades of ef…