MathDB
Maximum number of subsets

Source: Miklós Schweitzer 2010 ,P3

September 9, 2020
college contestsMiklos Schweitzercombinatoricsset theorySubsets

Problem Statement

Let Ai,i=1,2,,t A_i,i=1,2,\dots,t be distinct subsets of the base set {1,2,,n}\{1,2,\dots,n\} complying to the following condition AiAkAj \displaystyle A_ {i} \cap A_ {k} \subseteq A_ {j}for any 1i<j<kt.1 \leq i <j <k \leq t. Find the maximum value of t.t. Thanks @dgrozev