A note on distinct differences in $t$-intersecting families

Abstract: For a family $\mathcal{F}$ of subsets of ${1,2,\ldots,n}$, let $\mathcal{D}(\mathcal{F}) = {F\setminus G: F, G \in \mathcal{F}}$ be the collection of all (setwise) differences of $\mathcal{F}$. The family $\mathcal{F}$ is called a $t$-intersecting family, if for some positive integer $t$ and any two members $F, G \in \mathcal{F}$ we have $|F\cap G| \geq t$. The family $\mathcal{F}$ is simply called intersecting if $t=1$. Recently, Frankl proved an upper bound on the size of $\mathcal{D}(\mathcal{F})$ for the intersecting families $\mathcal{F}$. In this note we extend the result of Frankl to $t$-intersecting families.