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\title{The Sunflower Lemma of Erd\H{o}s and Rado}
\author{René Thiemann}
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\begin{abstract}
We formally define sunflowers and provide a formalization of
the sunflower lemma of Erd\H{o}s and Rado: whenever a set of size-$k$-sets has a larger cardinality 
than $(r - 1)^k \cdot k!$, then it contains a sunflower of cardinality $r$.
\end{abstract}

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