P. Motakis

activity

20112026

most citedA reflexive HI space with the hereditary Invariant Subspace Property

15 citations · 70 across the 38 of their papers we have counts for

collaborators

46 papers

math.FA2026

On complementation and $L$ -embedding of Lipschitz-free spaces in their biduals

Bruno M. Braga, Chris Gartland, Gilles Lancien +3

A closed subspace $E$ of a Banach space $F$ is \emph{ $L$ -embedded in $F$ } if there is a projection $P : F \to E$ such that $∥ x ∥ = ∥ P x ∥ + ∥ x - P x ∥$ for all $x \in F$ . We show that…

math.FA2026

On the $L$ -embeddability of Lipschitz-free spaces in their biduals

Bruno de Mendonça Braga, Chris Gartland, Gilles Lancien +3

A Banach space $X$ is $L$ -embedded in its bidual if there is a projection $P : X^{**} \to X$ such that $∥ x ∥ = ∥ P x ∥ + ∥ x - P x ∥$ for all $x \in X^{**}$ . We show that, as long as $X…

math.FA2026

Explicity Defined Norms on $J T_{*}$ Spaces

Spiros A. Argyros, Pavlos Motakis

We present a Banach space $X_{α}$ , equipped with an explicit norm, whose properties resemble those of the predual $J T_{*}$ of the James Tree space. In particular, $X_{α}$ admits a shrink…

math.FA2026

Expanders prevent Property (H)

Bruno de Mendonç Braga, Chris Gartland, Gilles Lancien +3

We show that if a sequence of expander graphs equi-coarsely embeds into a Banach space, then this Banach space fails Kasparov and Yu's Property (H). Consequently, no Banach space w…

math.FA2026

Embedding $ℓ_{2}$ and $J$ into subspaces of $J T$ and $J T^{*}$

Spiros A. Argyros, Manuel Gonzalez, Pavlos Motakis

In the first part of the paper we show that every closed subspace of $J T$ or $J T^{*}$ contains $ℓ_{2}$ complemented in $J T$ or $J T^{*}$ respectively, and $J T$ contains uncomplemented…

math.FA2025

On the uniform continuity of homeomorphisms between the spheres of $ℓ_{\infty}^{k}$ and $ℓ_{1}^{k}$

Bruno de Mendonça Braga, Chris Gartland, Gilles Lancien +3

We consider the problem of whether there is a sequence of homeomorphisms $(F_{k})_{k}$ between the unit spheres of the $k$ -dimensional Banach spaces $ℓ_{\infty}^{k}$ and $ℓ_{1}^{k}$ whic…

math.FA2025

Coordinate systems and distributional embeddings in Bourgain-Rosenthal-Schechtman spaces: a framework for operator reduction

Konstantinos Konstantos, Pavlos Motakis

For every $1 \leq α < ω_{1}$ , we construct an explicit unconditional finite-dimensional decomposition (FDD) $(X_{λ})_{λ \in T_{α}}$ of the Bourgain-Rosenthal-Schechtman space $R_α^{…

math.FA2024

The HI extension of the standard HI spaces

Spiros A. Argyros, Antonis Manoussakis, Pavlos Motakis

A Hereditarily Indecomposable (HI) Banach space $X$ admits an HI extension if there exists an HI space $Z$ such that $X$ is isomorphic to a subspace $Y$ of $Z$ and $Z / Y$ is of infi…

math.FA2024

$2$ -rotund norms for unconditional and symmetric sequence spaces

Stephen Dilworth, Denka Kutzarova, Pavlos Motakis

A reflexive Banach space with an unconditional basis admits an equivalent $1$ -unconditional $2 R$ norm and embeds into a reflexive space with a $1$ -symmetric $2 R$ norm. Partial resu…

math.FA2024

The compact operators on $c_{0}$ as a Calkin algebra

Pavlos Motakis, Daniele Puglisi

For a Banach space $X$ , let $L (X)$ denote the algebra of all bounded linear operators on $X$ and let $K (X)$ denote the compact operator ideal in $\mathcal{L}(X)…

math.FA2024★ 1 cited

On the complete separation of unique $ℓ_{1}$ spreading models and the Lebesgue property of Banach spaces

Harrison Gaebler, Pavlos Motakis, Bunyamin Sari

We construct a reflexive Banach space $X_{D}$ with an unconditional basis such that all spreading models admitted by normalized block sequences in $X_{D}$ are unifo…

math.FA2024

Orthogonal Factors of Operators on the Rosenthal $X_{p, w}$ spaces and the Bourgain-Rosenthal-Schechtman $R_{ω}^{p}$ space

Konstantinos Konstantos, Pavlos Motakis

For $1 < p < \infty$ , we show that the Rosenthal $X_{p, w}$ spaces and the Bourgain-Rosenthal-Schechtman $R_{ω}^{p}$ space have the factorization property and the primary factorization p…

math.FA2023

Multipliers on bi-parameter Haar system Hardy spaces

Richard Lechner, Pavlos Motakis, Paul F. X. Müller +1

Let $(h_{I})$ denote the standard Haar system on $[0, 1]$ , indexed by $I \in D$ , the set of dyadic intervals and $h_{I} \otimes h_{J}$ denote the tensor product $(s,t)\mapsto h_I(s…

math.FA2022

New characterizations of the unit vector basis of $c_{0}$ or $ℓ_{p}$

Peter G. Casazza, Stephen J. Dilworth, Denka Kutzarova +1

Motivated by Altshuler's famous characterization of the unit vector basis of $c_{0}$ or $ℓ_{p}$ among symmetric bases, we obtain similar characterizations among democratic bases and…

math.FA2022

Restricted invertibility of continuous matrix functions

Adrian Fan, Jack Montemurro, Pavlos Motakis +4

Motivated by an influential result of Bourgain and Tzafriri, we consider continuous matrix functions $A : R \to M_{n \times n}$ and lower $ℓ_{2}$ -norm bounds associated with…

math.FA2021★ 1 cited

On uniqueness and plentitude of subsymmetric sequences

Peter G. Casazza, Stephen J. Dilworth, Denka Kutzarova +1

We explore the diversity of subsymmetric basic sequences in spaces with a subsymmetric basis. We prove that the subsymmetrization $S u (T^{*})$ of Tsirelson's original Banach space pro…

math.FA2021★ 4 cited

Separable Spaces of Continuous Functions as Calkin Algebras

Pavlos Motakis

It is proved that for every compact metric space $K$ there exists a Banach space $X$ whose Calkin algebra $L (X) / K (X)$ is homomorphically isometric to $C (K)$ . Th…

math.FA2021

The complete separation of the two finer asymptotic $ℓ_{p}$ structures for $1 \leq p < \infty$

Spiros A. Argyros, Alexandros Georgiou, Antonis Manoussakis +1

For $1 \leq p < \infty$ , we present a reflexive Banach space $X_{awi}^{(p)}$ , with an unconditional basis, that admits $ℓ_{p}$ as a unique asymptotic model and does…

math.FA2021

The space $L_{1} (L_{p})$ is primary for $1 < p < \infty$

Richard Lechner, Pavlos Motakis, Paul F. X. Müller +1

The classical Banach space $L_{1} (L_{p})$ consists of measurable scalar functions $f$ on the unit square for which $$\|f\| = \int_0^1\Big(\int_0^1 |f(x,y)|^p dy\Big)^{1/p}dx < \infty.$…

math.FA2021

Variants of the James Tree space

S. A. Argyros, A. Manoussakis, P. Motakis

Recently, W. Cuellar Carrera, N. de Rancourt, and V. Ferenczi introduced the notion of $d_{2}$ -hereditarily indecomposable Banach spaces, i.e., non-Hilbertian spaces that do not cont…

math.MG2020

Coarse and Lipschitz universality

Florent P. Baudier, Gilles Lancien, Pavlos Motakis +1

In this paper we provide several \emph{metric universality} results. We exhibit for certain classes $\cC$ of metric spaces, families of metric spaces $(M_{i}, d_{i})_{i \in I}$ which ha…

math.FA2020

The geometry of Hamming-type metrics and their embeddings into Banach spaces

Florent P. Baudier, Gilles Lancien, Pavlos Motakis +1

Within the class of reflexive Banach spaces, we prove a metric characterization of the class of asymptotic- $c_{0}$ spaces in terms of a bi-Lipschitz invariant which involves metrics…

math.MG2020

Stochastic approximation of lamplighter metrics

Florent P. Baudier, Pavlos Motakis, Thomas Schlumprecht +1

We observe that embeddings into random metrics can be fruitfully used to study the $L_{1}$ -embeddability of lamplighter graphs or groups, and more generally lamplighter metric spaces…

math.FA2019★ 1 cited

The factorization property of $ℓ^{\infty} (X_{k})$

R. Lechner, P. Motakis, P. F. X. Müller +1

In this paper we consider the following problem: Let $X_{k}$ , be a Banach space with a normalized basis $(e_{(k, j)})_{j}$ , whose biorthogonals are denoted by $(e_{(k, j)}^{*})_{j}$ , for $k\…

On complementation and L-embedding of Lipschitz-free spaces in their biduals

On the L-embeddability of Lipschitz-free spaces in their biduals

Explicity Defined Norms on JT∗​ Spaces

Expanders prevent Property (H)

Embedding ℓ2​ and J into subspaces of JT and JT∗

On the uniform continuity of homeomorphisms between the spheres of ℓ∞k​ and ℓ1k​

Coordinate systems and distributional embeddings in Bourgain-Rosenthal-Schechtman spaces: a framework for operator reduction

The HI extension of the standard HI spaces

2-rotund norms for unconditional and symmetric sequence spaces

The compact operators on c0​ as a Calkin algebra

On the complete separation of unique ℓ1​ spreading models and the Lebesgue property of Banach spaces

Orthogonal Factors of Operators on the Rosenthal Xp,w​ spaces and the Bourgain-Rosenthal-Schechtman Rωp​ space

Multipliers on bi-parameter Haar system Hardy spaces

New characterizations of the unit vector basis of c0​ or ℓp​

Restricted invertibility of continuous matrix functions

On uniqueness and plentitude of subsymmetric sequences

Separable Spaces of Continuous Functions as Calkin Algebras

The complete separation of the two finer asymptotic ℓp​ structures for 1≤p<∞

The space L1​(Lp​) is primary for 1<p<∞

Variants of the James Tree space

Coarse and Lipschitz universality

The geometry of Hamming-type metrics and their embeddings into Banach spaces

Stochastic approximation of lamplighter metrics

The factorization property of ℓ∞(Xk​)

On complementation and $L$ -embedding of Lipschitz-free spaces in their biduals

On the $L$ -embeddability of Lipschitz-free spaces in their biduals

Explicity Defined Norms on $J T_{*}$ Spaces

Embedding $ℓ_{2}$ and $J$ into subspaces of $J T$ and $J T^{*}$

On the uniform continuity of homeomorphisms between the spheres of $ℓ_{\infty}^{k}$ and $ℓ_{1}^{k}$

$2$ -rotund norms for unconditional and symmetric sequence spaces

The compact operators on $c_{0}$ as a Calkin algebra

On the complete separation of unique $ℓ_{1}$ spreading models and the Lebesgue property of Banach spaces

Orthogonal Factors of Operators on the Rosenthal $X_{p, w}$ spaces and the Bourgain-Rosenthal-Schechtman $R_{ω}^{p}$ space

New characterizations of the unit vector basis of $c_{0}$ or $ℓ_{p}$

The complete separation of the two finer asymptotic $ℓ_{p}$ structures for $1 \leq p < \infty$

The space $L_{1} (L_{p})$ is primary for $1 < p < \infty$

The factorization property of $ℓ^{\infty} (X_{k})$