6 citations · 6 across the 4 of their papers we have counts for
5 papers
Bijection between positive clusters and projectively signed exceptional sequences
Shujian Chen, Kiyoshi Igusa
In 2017, Igusa and Todorov gave a bijection between signed exceptional sequences and ordered partial clusters. In this paper, we show that every term in an exceptional sequence is…
Generalized Goulden-Yong duals and signed minimal factorizations
Shujian Chen, Kiyoshi Igusa
In this paper, we give two combinatorial ways to study signed exceptional sequences. First, we show the equivalence between one-way reflections and relatively projective representa…
Borsuk-Ulam theorems for products of spheres and Stiefel manifolds revisited
Yu Hin Chan, Shujian Chen, Florian Frick +1
We give a different and possibly more accessible proof of a general Borsuk--Ulam theorem for a product of spheres, originally due to Ramos. That is, we show the non-existence of ce…
Free extensions and Lefschetz properties, with an application to rings of relative coinvariants
Chris McDaniel, Shujian Chen, Anthony Iarrobino +1
Graded Artinian algebras can be regarded as algebraic analogues of cohomology rings (in even degrees) of compact topological manifolds. In this analogy, a free extension of a base…
Splitting loops and necklaces: Variants of the square peg problem
Jai Aslam, Shujian Chen, Florian Frick +3
Toeplitz conjectured that any simple planar loop inscribes a square. Here we prove variants of Toeplitz' square peg problem. We prove Hadwiger's 1971 conjecture that any simple loo…