January 2021

One kind of construction on sunflower with two petals*

A sunflower (or ∆-system) with k petals and a core Y is a collection of sets S1,⋯, Sk such that Si∩Sj=Y for all i≠j; the sets S1\Y,⋯, Sk\ Y, are petals. In this paper, we first give a sufficient condition for the existence of a sunflower with 2 petals. Let F={A,B,C} be a family of subsets of a set { a1,⋯,am , b1,⋯,bn , c1,⋯,cn } with  and A={a1,⋯,am}, B={ b1,⋯,bn } and C={ c1,⋯,cn } are...

Author(s): Jiyun Guo, Guanshu Wang and Baiguang Cai