Armin Schikorra

collaborators

4 papers

math.FA2026

Non-improvability of sharp endpoint estimates

ZdenÄk Mihula, LuboÅ¡ Pick, Armin Schikorra

For an integer $n$ and the parameter $I^^{3} \in (0, n)$ , the Riesz potential $I_{I^}^{3}$ is known to take boundedly $L^{1} (R^{n})$ into $L^{\frac{n}{n - I ^ ^{3}}, \infty} (R^{n})$ , and als…

math.AP2026

A remark on staircase laminates in restricted sets

Igor Buchowiec, Pholphum Kamthorntaksina, Katarzyna Mazowiecka +2

We slightly extend the convex integration via staircase laminate toolbox recently developed by Kleiner, MÃ¼ller, SzÃ©kelyhidi, and Xie. As an example we revisit the proof by Astala…

math.AP2026

Existence of nontrival $n$ -harmonic maps via min-max methods

Dorian Martino, Katarzyna Mazowiecka, Armin Schikorra

For any $n \geq 3$ and any closed manifold $N$ with $I ¨ _{n + k} (N) \neq = {0}$ for some $k \geq 0$ , we establish the existence of nontrivial $n$ -harmonic maps fro…

math.AP2025

Local well-posedness for cubic fractional SchrÃ¶dinger equations with derivatives on the right-hand side

Ahmed Dughayshim, Silvino Reyes Farina, Armin Schikorra

For $s \in (\frac{1}{2}, 1]$ we investigate well-posedness of the equation \[ \left ( i \partial_t + (-Î)^{s} \right ) u = \left (|D|^{1-2s} |u|^2 \right)\ |D|^{2s-1} u \] under sm…

Non-improvability of sharp endpoint estimates

A remark on staircase laminates in restricted sets

Existence of nontrival n-harmonic maps via min-max methods

Local well-posedness for cubic fractional SchrÃ¶dinger equations with derivatives on the right-hand side

Existence of nontrival $n$ -harmonic maps via min-max methods