Mikael Hansson

activity

20152017

collaborators

3 papers

math.CO2017

Topology of posets with special partial matchings

Nancy Abdallah, Mikael Hansson, Axel Hultman

Special partial matchings (SPMs) are a generalisation of Brenti's special matchings. Let a \emph{pircon} be a poset in which every non-trivial principal order ideal is finite and a…

math.CO2016

Generalised Ramsey numbers for two sets of cycles

Mikael Hansson

We determine several generalised Ramsey numbers for two sets $Γ_{1}$ and $Γ_{2}$ of cycles, in particular, all generalised Ramsey numbers $R (Γ_{1}, Γ_{2})$ such that $Γ_{1}$ or $Γ_{2}$ contains…

math.CO2015

The Bruhat order on conjugation-invariant sets of involutions in the symmetric group

Mikael Hansson

Let $I_{n}$ be the set of involutions in the symmetric group $S_{n}$ , and for $A \subseteq {0, 1, \dots, n}$ , let \[ F_n^A=\{σ\in I_n \mid \text{ $σ$ has $a$ fixed points for some $a \i…