One of my research problem can be reduced to a question of the following form



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> Given a set family $\mathcal{F}$ of $[n]$ , such that every element of $[n]$ lies in exactly $K$ sets in $\mathcal{F}$, can w partition $\mathcal{F}$ into $K$ subfamilies $\mathcal{F}\_i$ such that each subfamily is a partition of $[n]$?
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Edit: It looks like the problem as stated admits an easy counterexample. I have posted a more interesting version [here](https://mathoverflow.net/questions/442538/jigsaw-puzzle-on-set-family-ii).



"JigSaw Puzzle" on Set Family
No. E.g., let $n=3$ and $\mathcal F=\{\{1,2\},\{1,3\},\{2,3\}\}$, so that $K=2$. However, no subset of $\mathcal F$ is a partition of $[n]$.


