[HTML][HTML] A non-Golod ring with a trivial product on its Koszul homology

L Katthän - Journal of Algebra, 2017 - Elsevier
We present a monomial ideal a⊂ S such that S/a is not Golod, even though the product in its
Koszul homology is trivial. This constitutes a counterexample to a well-known result by …

Simple crystallizations of 4-manifolds

B Basak, J Spreer - Advances in Geometry, 2016 - degruyter.com
Minimal crystallizations of simply connected PL 4-manifolds are very natural objects. Many
of their topological features are reflected in their combinatorial structure which, in addition, is …

Hopf triangulations of spheres and equilibrium triangulations of projective spaces

W Kühnel, J Spreer - arxiv preprint arxiv:2309.12728, 2023 - arxiv.org
Following work by the first author and Banchoff, we investigate triangulations of real and
complex projective spaces of real and complex dimension $ k $ that are adapted to the …

On the Voronoi conjecture for combinatorially Voronoi parallelohedra in Dimension 5

MD Sikiric, A Garber, A Magazinov - SIAM journal on discrete mathematics, 2020 - SIAM
In a recent paper, Garber, Gavrilyuk, and Magazinov Discrete Comput. Geom., 53 (2015),
pp. 245--260 proposed a sufficient combinatorial condition for a parallelohedron to be …

[HTML][HTML] A necessary condition for the tightness of odd-dimensional combinatorial manifolds

J Spreer - European Journal of Combinatorics, 2016 - Elsevier
We present a necessary condition for (ℓ− 1)-connected combinatorial (2 ℓ+ 1)-manifolds to
be tight. As a corollary, we show that there is no tight combinatorial three-manifold with first …