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math.CO2019
Cyclic Flats of Binary Matroids
Ragnar Freij-Hollanti, Matthias Grezet, Camilla Hollanti +1
In this paper, first steps are taken towards characterising lattices of cyclic flats that belong to matroids that can be represented over a prescribed finite f…
math.CO2008
Enumeration of derangements with descents in prescribed positions
Niklas Eriksen, Ragnar Freij, Johan Wastlund
We enumerate derangements with descents in prescribed positions. A generating function was given by Guo-Niu Han and Guoce Xin in 2007. We give a combinatorial proof of this result,…