18 citations · 24 across the 10 of their papers we have counts for
11 papers
Extension-closed subcategories over hypersurfaces of finite or countable CM-representation type
Kei-ichiro Iima, Ryo Takahashi
Let k be an algebraically closed uncountable field of characteristic zero. Let R be a complete local hypersurface over k. Denote by CM(R) the category of maximal Cohen-Macaulay R-m…
Vanishing of DHKK complexities for singularity categories and generation of syzygy modules
Tokuji Araya, Kei-ichiro Iima, Ryo Takahashi
Let R be a commutative noetherian ring. In this paper, we study, for the singularity category of R, the vanishing of the complexity in the sense of Dimitrov, Haiden, Kat…
When is a subcategory Serre or torsionfree?
Kei-ichiro Iima, Hiroki Matsui, Kaori Shimada +1
Let R be a commutative noetherian ring. Denote by mod R the category of finitely generated R-modules. In the present paper, we first provide various sufficient (and necessary) cond…
Generation in singularity categories of hypersurfaces of countable representation type
Tokuji Araya, Kei-ichiro Iima, Maiko Ono +1
The Orlov spectrum and Rouquier dimension are invariants of a triangulated category to measure how big the category is, and they have been studied actively. In this paper, we inves…
On the ideal case of a conjecture of Auslander and Reiten
Olgur Celikbas, Kei-ichiro Iima, Arash Sadeghi +1
A celebrated conjecture of Auslander and Reiten claims that a finitely generated module that has no extensions with over an Artin algebra must be projective. Th…
Perfect linkage of Cohen--Macaulay modules over Cohen--Macaulay rings
Kei-ichiro Iima, Ryo Takahashi
In this paper, we introduce and study the notion of linkage by perfect modules, which we call perfect linkage, for Cohen-Macaulay modules over Cohen--Macaulay local rings. We explo…