Tattwamasi Amrutam

activity

20182026

most citedA generalized Powers averaging property for commutative crossed products

6 citations · 14 across the 18 of their papers we have counts for

collaborators

21 papers

math.OA2026

IRA Rigidity and boomerang subalgebras of group von Neumann algebras

Tattwamasi Amrutam, Yair Glasner, Yair Hartman +1

We introduce the notion of Boomerang subalgebras of group von Neumann algebras and study their general properties. We show that every Boomerang subalgebra of $L (Γ)$ is the group vo…

math.OA2026

Inner $C^{*}$ -Selfless Groups

Tattwamasi Amrutam, Mario Klisse, Matteo Pagliero

We introduce the notion of inner $C^{*}$ -selfless groups and study their structural properties. We prove a Fourier coefficient extraction theorem for invariant subalgeb…

math.OA2026

Invariant random subgroups of $C^{*}$ -simple groups

Tattwamasi Amrutam, Mehrdad Kalantar

Let $Γ$ be a countable discrete $C^{*}$ -simple group. Let $μ$ be a $Γ$ -invariant Borel probability measure on $Sub (Γ)$ , i.e., an IRS. We show that $μ$ -almost every subgroup $H…

math.OA2026

The $C^{*}$ --ISR Property for $PSL_{n} (Z)$

Tattwamasi Amrutam

A discrete group $Γ$ has the \emph{ $C^{*}$ --ISR property} if every unital $Γ$ --invariant $C^{*}$ --subalgebra $A \subseteq C_{r}^{*} (Γ)$ is of the form $C_{r}^{*} (N)$ for a normal subgroup $N\tr…

math.OA2026

Uniformly recurrent subalgebras in finite von Neumann algebras

Tattwamasi Amrutam, Pierre Fima, Yongle Jiang

We introduce the notion of a uniformly recurrent subalgebra (URA) for a trace-preserving action of a countable discrete group $Γ$ on a finite von Neumann algebra $M$ , providing an…

math.OA2026

Simplicity of q-Gaussian C*-algebras

Tattwamasi Amrutam, David Jekel, Mateusz Wasilewski

We show that q-Gaussian $C^{*}$ -algebras for $q \in (- 1, 1)$ have the Dixmier averaging property, and hence are simple with a unique trace. We argue by combining rapid decay and spec…

math.OA2026

Relative invariant subalgebra rigidity for Thompson's group $F$

Tattwamasi Amrutam, Artem Dudko

We prove that Thompson's group $F$ satisfies the relative invariant subalgebra rigidity property with respect to its commutator subgroup: every von Neumann subalgebra of $L (F)$ tha…

math.OA2026

$C^{*}$ -simplicity, confined subalgebras, and operator algebraic uniform recurrence

Tattwamasi Amrutam, Yongle Jiang

We introduce the notion of confined subalgebras in the context of the group von Neumann algebra. We also define Uniformly Recurrent States -- an operator-algebraic analog of Unifor…

math.OA2026

On Relative Invariant Subalgebra Rigidity Property

Tattwamasi Amrutam

A countable discrete group $Γ$ is said to have the relative ISR-property if for every non-trivial normal subgroup $N ⊴ Γ$ and every von Neumann subalgebra $\mathcal{M}\…

math.OA2026

Rigidity of Generalized Furstenberg Boundaries and Applications to Intermediate Crossed Products

Tattwamasi Amrutam, Chunlin Liu

We develop a relative boundary theory for actions of discrete groups on compact spaces and use it to derive rigidity results for reduced crossed products. For a discrete group $Γ$ …

math.OA2024

Strict comparison in reduced group $C^{*}$ -algebras

Tattwamasi Amrutam, David Gao, Srivatsav Kunnawalkam Elayavalli +1

We prove that for every $n \geq 2$ , the reduced group $C^{*}$ -algebras of the countable free groups $C_{r}^{*} (F_{n})$ have strict comparison. Our method works in a general setting…

math.DS2024

Relative stationary dynamical systems

Tattwamasi Amrutam, Martin Klötzer, Hanna Oppelmayer

Let $G$ be a locally compact second countable group equipped with an admissible non-degenerate Borel probability measure $μ$ . We generalize the notion of $μ$ -stationary systems to…

math.OA2023

Powers averaging for actions on $C (X)$ -algebras

Tattwamasi Amrutam, Ilan Hirshberg, Apurva Seth

Given a unital $C (X)$ -algebra $A$ discrete group $Γ$ and an action $α : Γ \to aut (A)$ which leaves $C (X)$ invariant and such that $C (X) ⋊_{α, r} Γ$ is simple, and a $2$ -co…

math.OA2023

Intermediate crossed product $C^{*}$ -algebras

Tattwamasi Amrutam, Ilan Hirshberg, Apurva Seth

Let $B$ be a separable $C^{*}$ -algebra, let $Γ$ be a discrete countable group, let $α : Γ \to Aut (B)$ be an action, and let $A$ be an invariant subalgebra. We find certain freen…

math.OA2023★ 1 cited

On the amenable subalgebras of group von Neumann algebras

Tattwamasi Amrutam, Yair Hartman, Hanna Oppelmayer

We approach the study of sub-von Neumann algebras of the group von Neumann algebra $L Γ$ for countable groups $Γ$ from a dynamical perspective. It is shown that $L (Γ)$ admits a maxi…

math.OA2023

Non-Abelian Factors for Actions of $Z$ and Other Non- $C^{*}$ -Simple Groups

Tattwamasi Amrutam, Eli Glasner, Yair Glasner

Let $Γ$ be a countable group and $(X, Γ)$ a compact topological dynamical system. We study the question of the existence of an intermediate $C^{*}$ -subalgebra $A$ $$C^{*}_{…

math.OA2022★ 4 cited

Subalgebras, subgroups, and singularity

Tattwamasi Amrutam, Yair Hartman

This paper concerns the non-commutative analog of the Normal Subgroup Theorem for certain groups. Inspired by Kalantar-Panagopoulos, we show that all $Γ$ -invariant subalgebras of $…

math.OA2022

On invariant von Neumann subalgebras rigidity property

Tattwamasi Amrutam, Yongle Jiang

We say that a countable discrete group $Γ$ satisfies the invariant von Neumann subalgebras rigidity (ISR) property if every $Γ$ - invariant von Neumann subalgebra $M$ in $…

math.OA2021★ 6 cited

A generalized Powers averaging property for commutative crossed products

Tattwamasi Amrutam, Dan Ursu

We prove a generalized version of Powers' averaging property that characterizes simplicity of reduced crossed products $C (X) ⋊_{λ} G$ , where $G$ is a countable discrete group, a…

math.OA2018★ 1 cited

On Intermediate $C^{}$ -subalgebras of $C^{}$ -simple Group Actions

Tattwamasi Amrutam

We show that for a large class of actions $Γ ↷ A$ of $C^{*}$ -simple groups $Γ$ on unital $C^{*}$ -algebras $A$ , including any non-faithful action of a…

math.OA2018★ 2 cited

On simplicity of intermediate C*-algebras

Tattwamasi Amrutam, Mehrdad Kalantar

We prove simplicity of all intermediate $C^{*}$ -algebras $C_{r}^{*} (Γ) \subseteq B \subseteq Γ ⋉_{r} C (X)$ in the case of minimal actions of $C^{*}$ -simple groups $Γ$ on comp…

IRA Rigidity and boomerang subalgebras of group von Neumann algebras

Inner C∗-Selfless Groups

Invariant random subgroups of C∗-simple groups

The C∗--ISR Property for PSLn​(Z)

Uniformly recurrent subalgebras in finite von Neumann algebras

Simplicity of q-Gaussian C*-algebras

Relative invariant subalgebra rigidity for Thompson's group F

C∗-simplicity, confined subalgebras, and operator algebraic uniform recurrence

On Relative Invariant Subalgebra Rigidity Property

Rigidity of Generalized Furstenberg Boundaries and Applications to Intermediate Crossed Products

Strict comparison in reduced group C∗-algebras

Relative stationary dynamical systems

Powers averaging for actions on C(X)-algebras

Intermediate crossed product C∗-algebras

On the amenable subalgebras of group von Neumann algebras

Non-Abelian Factors for Actions of Z and Other Non-C∗-Simple Groups

Subalgebras, subgroups, and singularity

On invariant von Neumann subalgebras rigidity property

A generalized Powers averaging property for commutative crossed products

On Intermediate C∗-subalgebras of C∗-simple Group Actions

On simplicity of intermediate C*-algebras

Inner $C^{*}$ -Selfless Groups

Invariant random subgroups of $C^{*}$ -simple groups

The $C^{*}$ --ISR Property for $PSL_{n} (Z)$

Relative invariant subalgebra rigidity for Thompson's group $F$

$C^{*}$ -simplicity, confined subalgebras, and operator algebraic uniform recurrence

Strict comparison in reduced group $C^{*}$ -algebras

Powers averaging for actions on $C (X)$ -algebras

Intermediate crossed product $C^{*}$ -algebras

Non-Abelian Factors for Actions of $Z$ and Other Non- $C^{*}$ -Simple Groups

On Intermediate $C^{}$ -subalgebras of $C^{}$ -simple Group Actions