71 citations · 321 across the 37 of their papers we have counts for
42 papers
Combinatorial Hopf algebras from restriction species with preorder cuts
Gunnar Fløystad
We get new Hopf algebras (HA): 1. A wealth of quotient HA's of the Malvenuto-Reutenauer HA (the Loday-Ronco HA being a special case). They consist of the permutations avoiding an {…
Polarizations of Artin monomial ideals
Gunnar Fløystad, Ine Gabrielsen, Amir Mafi
We show that any polarization of an Artin monomial ideal defines a triangulated ball. This proves a conjecture of A.Almousa, H.Lohne and the first author. Geometrically, polarizati…
Eight times four bialgebras of hypergraphs, cointeractions, and chromatic polynomials
Kurusch Ebrahimi-Fard, Gunnar Fløystad
We consider the bialgebra of hypergraphs, a generalization of Schmitt's Hopf algebra of graphs, and show it has a cointeracting bialgebra. So one has a double bialgebra in the sens…
Partitons of vertices and facets in trees and stacked simplicial complexes
Gunnar Fløystad
For stacked simplicial complexes, (special subclasses of such are: trees, triangulations of polygons, stacked polytopes), we give an explicit bijection between partitions of facets…
Triangulations of polygons and stacked simplicial complexes: separating their Stanley-Reisner ideals
Gunnar Fløystad, Milo Orlich
A triangulation of a polygon has an associated Stanley-Reisner ideal. We obtain a full algebraic and combinatorial understanding of these ideals, and describe their separated model…
Shift modules, strongly stable ideals, and their dualities
Gunnar Fløystad
We enrich the setting of strongly stable ideals (SSI): We introduce shift modules, a module category encompassing SSI's. The recently introduced duality on SSI's is given an effect…