arXiv subjects

Natalie Nikitin

Publications and source records attributed to Natalie Nikitin.

3 recordsLinked to original sources

arXiv2019

Measurable regularity of infinite-dimensional Lie groups based on Lusin measurability

We discuss Lebesgue spaces $\mathcal{L}^p([a,b],E)$ of Lusin measurable vector-valued functions and the corresponding vector spaces $AC_{L^p}([a,b],E)$ of absolutely continuous functions. These can be used to construct Lie groups $AC_{L^p}([a,b],G)$ of absolutely continuous functions with values in an infinite-dimensional Lie group $G$. We extend the notion of $L^p$-regularity of infinite-dimensional Lie groups introduced by Glöckner to this setting and adopt several results and tools.

math.FA↗

arXiv2016

Exponential laws for spaces of differentiable functions on topological groups

Smooth functions $f:G\to E$ from a topological group $G$ to a locally convex space $E$ were considered by Riss (1953), Boseck, Czichowski and Rudolph (1981), Beltiţă and Nicolae (2015), and others, in varying degrees of generality. The space $C^\infty(G,E)$ of such functions carries a natural topology, the compact-open $C^\infty$-topology. For topological groups $G$ and $H$, we show that $C^\infty(G\times H,E)\cong C^\infty(G,C^\infty(H,E))$ as a locally convex space, whenever both $G$ and $H$ are metrizable or both $G$ and $H$ are locally compact. Likewise, $C^k(G, C^l(H,E))$ can be identified with a suitable space of functions on $G\times H$.

math.FA↗

arXiv2015

Exponential laws for weighted function spaces and regularity of weighted mapping groups

Let $E$ be a locally convex space, $U\subseteq\mathbb{R}^n$ as well as $V\subseteq\mathbb{R}^m$ be open and $k,l\in\mathbb{N}_0\cup\left\{\infty\right\}$. Locally convex spaces $C^{k,l}(U\times V,E)$ of functions with different degrees of differentiability in the $U$- and $V$-variable were recently studied by H.Alzaareer, who established an exponential law of the form $C^{k,l}(U\times V,E)\cong C^k(U,C^l(V,E))$. We establish an analogous exponential law $C^{k,l}_{\mathcal{W}_1\otimes\mathcal{W}_2}(U\times V,E)\cong C^k_{\mathcal{W}_1}(U,C^l_{\mathcal{W}_2}(V,E))$ for suitable spaces of weighted $C^{k,l}$-maps, as well as an analogue for spaces of weighted continuous functions on locally compact spaces. The results entail that certain Lie groups $C^l_\mathcal{W}(U,H)$ of weighted mappings introduced by B.Walter are $C^k$-regular, for each $C^k$-regular Lie group $H$ modeled on a locally convex space and a suitable set of weights $\mathcal{W}$.

math.FA↗