6 papers
A Finite-Geometric Obstruction and a Polytopal Separation of Buchstaber Invariants
Suyoung Choi, Hyeontae Jang
We construct a polytopal simplicial sphere that admits a mod 2 characteristic map but no mod 3 characteristic map, and hence no integral one. This shows that the Buchstaber number…
On the toric lifting properties for simplicial -spheres
Suyoung Choi, Yuanxin Guan, Hyeontae Jang +1
We study the lifting problem for mod characteristic maps over simplicial -spheres. Using a bad-block partition of the universal complex , we prove an avoi…
Small covers as pullbacks from the simplex
Suyoung Choi, Hyeontae Jang, Younghan Yoon
We introduce and study small covers that are pullbacks from the simplex, extending pullbacks from the linear model. Our main result gives several equivalent characterizations of th…
Complete non-singular toric varieties with Picard number 4
Suyoung Choi, Hyeontae Jang, Mathieu Vallée
We classify all complete non-singular toric varieties with Picard number four via a combinatorial framework based on fanlike simplicial spheres and characteristic maps. This classi…
Stellar subdivisions, wedges and Buchstaber numbers
Suyoung Choi, Hyeontae Jang
A seed is a PL sphere that is not obtainable by a wedge operation from any other PL sphere. In this paper, we study two operations on PL spheres, known as the stellar subdivision a…
Toric wedge induction and toric lifting property for piecewise linear spheres with a few vertices
Suyoung Choi, Hyeontae Jang, Mathieu Vallée
Let be an -dimensional piecewise linear sphere on , where . There are a canonical action of -dimensional torus on the moment-angle complex $\mat…