9 papers
Balanced notation for -rigid pairs
Kiyoshi Igusa, Gordana Todorov
We introduce a new notation for -rigid pairs called ``balanced pairs''. The notation allows for simplification of some formulas, for example the Jasso category and it…
Short history of signed exceptional sequences
Kiyoshi Igusa, Gordana Todorov
Whereas exceptional sequences have a long history with many well-known connections to combinatorics, signed exceptional sequences are relatively recent. The authors introduced this…
More ghost modules I
Kiyoshi Igusa
Ghost modules were introduced in [I3] without definitions or proofs. We also introduced stability diagrams or "relative pictures" for torsion classes and torsion-free classes for r…
Picture groups and maximal green sequences
Kiyoshi Igusa, Gordana Todorov
We show that picture groups are directly related to maximal green sequences for valued Dynkin quivers of finite type. Namely, there is a bijection between maximal green sequences a…
On the functoriality of the space of equivariant smooth -cobordisms
Thomas Goodwillie, Kiyoshi Igusa, Cary Malkiewich +1
We construct an -functor that takes each smooth -manifold with corners to the space of equivariant smooth -cobordisms . We al…
Generalized Grassmann invariant-redrawn
Kiyoshi Igusa
This is my old unpublished paper called "The generalized Grassmann invariant". It shows how "pictures" also known as "Peiffer diagrams" represent elements of for any group $…