Takefumi Nosaka

activity

20102026

most citedCentral extensions of groups and adjoint groups of quandles

9 citations · 40 across the 33 of their papers we have counts for

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3 papers · 1 filter

math.GT2026

Gröbner Bases for Alexander Fitting Ideals of Links

Takefumi Nosaka, Kotaro Shimizu

Multivariable Alexander theory produces Fitting ideals without preferred generators. After fixing a coefficient field and a monomial order, we represent these ideals by reduced Grö…

math.GT2026

Type Annihilation for Classifying Maps of Rack Spaces

Takefumi Nosaka

We study the classifying map $c\colon BX\to K(\As(X),1)$ of a rack $X$ of finite type. Let $t = \Type(X)$. We prove that $t c_{n *} = 0$ for every $n \geq 2$ when $X$ is connected, and t…

math.GT2026

Chern--Simons-type $3$ -cocycles and $Q / Z$ -torsion in the third homology of discrete diffeomorphism groups

Takefumi Nosaka

We prove that the third integral group homology of both the volume-preserving diffeomorphism group and the strict contactomorphism group of the standard $3$-sphere contains \((\m…

Gröbner Bases for Alexander Fitting Ideals of Links

Type Annihilation for Classifying Maps of Rack Spaces

Chern--Simons-type 3-cocycles and Q/Z-torsion in the third homology of discrete diffeomorphism groups

Chern--Simons-type $3$ -cocycles and $Q / Z$ -torsion in the third homology of discrete diffeomorphism groups