I. Vergara

activity

20142026

most citedEuropium Underneath Graphene on Ir(111): Intercalation Mechanism, Magnetism, and Band Structure

78 citations · 244 across the 20 of their papers we have counts for

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12 papers · 1 filter

math.GR2026

Relative property (T) for uniformly bounded representations

Guillaume Dumas, Ignacio Vergara

For pairs $(G, H)$ , where $G$ is a locally compact group and $H$ is a closed subgroup of $G$ , we introduce analogous versions of the full group $C^{*}$ -algebra and the Fourie…

math.GR2026

$L_{1}$ Actions and Embeddings of Property A Spaces

Chris Gartland, Ignacio Vergara, Tianyi Zheng

We provide several new characterizations of Property A for bounded degree graphs. In particular, we show that $(X, d)$ has Property A if and only if there is a proper gauge $ω$ such…

math.GR2025

Some remarks on $M_{d}$ -multipliers and approximation properties

Ignacio Vergara

We prove an extension property for $M_{d}$ -multipliers from a subgroup to the ambient group, showing that $M_{d + 1} (G)$ is strictly contained in $M_{d} (G)$ whenever $G$ contains a free…

math.GR2024

Quasi-trees, Lipschitz free spaces, and actions on $ℓ^{1}$

Ignacio Vergara

We show that the Lipschitz free space of a countable simplicial quasi-tree is isomorphic to $ℓ^{1}$ . As a consequence, every finitely generated group with Property (QT) of Bestvin…

math.GR2024

A connection between Lipschitz and Kazhdan constants for groups of homeomorphisms of the real line

Ignacio Vergara

We exhibit an obstruction for groups with Relative Property (T) to act on the real line by bi-Lipschitz homeomorphisms. This condition is expressed in terms of the Lipschitz and Ka…

math.GR2024

An invitation to weak amenability, after Cowling and Haagerup

Ignacio Vergara

We present an introduction to weak amenability for locally compact groups, and a survey of some of the most important results regarding this property.

math.GR2024

Property $(TTT)$ and the Cowling--Haagerup constant

Ignacio Vergara

We show that Property $(TTT)$ is an obstruction to weak amenability with Cowling--Haagerup constant $1$ . More precisely, if $G$ is a countable group and $H$ is an infinite…

math.GR2022★ 1 cited

Property (T) for uniformly bounded representations and weak*-continuity of invariant means

Ignacio Vergara

For every $c \geq 1$ , we define a strengthening of Kazhdan's Property (T) by considering uniformly bounded representations $π$ with fixed bound $∣ π ∣ \leq c$ . We carry out a systemati…

math.GR2022★ 2 cited

Hyperbolicity and uniformly Lipschitz affine actions on subspaces of $L^{1}$

Ignacio Vergara

We show that every hyperbolic group has a proper uniformly Lipschitz affine action on a subspace of an $L^{1}$ space. We also prove that every acylindrically hyperbolic group has a u…

math.GR2022★ 1 cited

The $M_{d}$ -Approximation Property and Unitarisability

Ignacio Vergara

We define a strengthening of the Haagerup-Kraus approximation property by means of the subalgebras of Herz-Schur multipliers $M_{d} (G)$ ( $d \geq 2$ ) introduced by Pisier. We show that…

math.GR2021

Weak amenability of free products of hyperbolic and amenable groups

Ignacio Vergara

We show that, if $G$ is an amenable group and $H$ is a hyperbolic group, then the free product $G * H$ is weakly amenable. A key ingredient in the proof is the fact that $G\ast H…

math.GR2021

Almost invariant CND kernels and proper uniformly Lipschitz actions on subspaces of $L^{1}$

Ignacio Vergara

We define the notion of almost invariant conditionally negative definite kernel and use it to give a characterisation of groups admitting a proper uniformly Lipschitz affine action…

Relative property (T) for uniformly bounded representations

L1​ Actions and Embeddings of Property A Spaces

Some remarks on Md​-multipliers and approximation properties

Quasi-trees, Lipschitz free spaces, and actions on ℓ1

A connection between Lipschitz and Kazhdan constants for groups of homeomorphisms of the real line

An invitation to weak amenability, after Cowling and Haagerup

Property (TTT) and the Cowling--Haagerup constant

Property (T) for uniformly bounded representations and weak*-continuity of invariant means

Hyperbolicity and uniformly Lipschitz affine actions on subspaces of L1

The Md​-Approximation Property and Unitarisability

Weak amenability of free products of hyperbolic and amenable groups

Almost invariant CND kernels and proper uniformly Lipschitz actions on subspaces of L1

$L_{1}$ Actions and Embeddings of Property A Spaces

Some remarks on $M_{d}$ -multipliers and approximation properties

Quasi-trees, Lipschitz free spaces, and actions on $ℓ^{1}$

Property $(TTT)$ and the Cowling--Haagerup constant

Hyperbolicity and uniformly Lipschitz affine actions on subspaces of $L^{1}$

The $M_{d}$ -Approximation Property and Unitarisability

Almost invariant CND kernels and proper uniformly Lipschitz actions on subspaces of $L^{1}$