Fyrsta málstofa haustsins verður föstudaginn 23. september kl 10:30 í Naustinu húsi Endurmenntunar. Fyrirlesari er Atli Fannar Franklín, Raunvísindastofnun háskólans.
Titill hans er Counting score sequences.
Abstract: The score sequence of a tournament is the sequence of the out-degrees of its vertices arranged in nondecreasing order. The problem of counting score sequences of a tournament with n vertices is more than 100 years old. In 2013 Hanna conjectured a surprising and elegant recursion for these numbers. We settle this conjecture in the affirmative by showing that it is a corollary to our main theorem, which is a factorization of the generating function for score sequences with a distinguished index. We also derive a closed formula and faster algorithm for the number of score sequences.