Balazs Patkos: When you hear the instruction ?TRACE, 
TRACE?, take up the
following position
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Abstract: A family \cF \subseteq 2^{[n]} is l-trace k-Sperner if for
any l-subset X of [n] the family \{F \cap X: F \in \cF \} is
k-Sperner. We list some old results and prove some new ones.