Lars-Luca Langer

activity

20242026

collaborators

3 papers

math.FA2026

Operator $K$ -Positivity Preserver

Lars-Luca Langer

We characterize positivity preserving maps $T : B (H)_{h} \otimes R [x_{1}, \dots, x_{n}] \to B (H)_{h} \otimes R [x_{1}, \dots, x_{n}]$ on $R^{n}$ and…

math.FA2025

Characterization of Matrix $K$ -Positivity Preserver for $K = R^{n}$ and for Compact Sets $K \subseteq R^{n}$

Philipp J. di Dio, Lars-Luca Langer

For any closed $K \subseteq R^{n}$ , in [P.\ J.\ di\,Dio, K.\ SchmÃ¼dgen: $K$ -Positivity Preserver and their Generators, SIAM J.\ Appl.\ Algebra Geom.\ 9 (2025), 794--824] all…

math.FA2024

The Hadamard Product of Moment Sequences, Diagonal Positivity Preservers, and their Generators

Philipp J. di Dio, Lars-Luca Langer

In this work we investigate special aspects of positivity preservers and especially diagonal positivity preservers, i.e., linear maps $T:\mathbb{R}[x_1,\dots,x_n]\to\mathbb{R}[x_1,…

Operator K-Positivity Preserver

Characterization of Matrix K-Positivity Preserver for K=Rn and for Compact Sets K⊆Rn

The Hadamard Product of Moment Sequences, Diagonal Positivity Preservers, and their Generators

Operator $K$ -Positivity Preserver

Characterization of Matrix $K$ -Positivity Preserver for $K = R^{n}$ and for Compact Sets $K \subseteq R^{n}$