Abstract

We formally define sunflowers and provide a formalization of the sunflower lemma of Erdős and Rado: whenever a set of size-k-sets has a larger cardinality than (r – 1)^k * k!, then it contains a sunflower of cardinality r.

BibTeX

@article{Sunflowers-AFP,
  author  = {René Thiemann},
  title   = {The Sunflower Lemma of Erdős and Rado},
  journal = {Archive of Formal Proofs},
  month   = feb,
  year    = 2021,
  note    = {\url{https://isa-afp.org/entries/Sunflowers.html},
            Formal proof development},
  ISSN    = {2150-914x},
}