Search arXiv⌕ Search

arXiv · 0709.4122

Symmetries in projective multiresolution analyses

Abstract

We give an equivariant version of Packer and Rieffel's theorem on sufficient conditions for the existence of orthonormal wavelets in projective multiresolution analyses. The scaling functions that generate a projective multiresolution analysis are supposed to be invariant with respect to some finite group action. We give sufficient conditions for the existence of wavelets with similar invariance.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Kjetil Røysland. 2007-09-26. Symmetries in projective multiresolution analyses. https://arxiv.org/abs/0709.4122

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

A Sharp Planar Fractional Isoperimetric Inequality

In this article, we prove the sharp form of the fractional isoperimetric inequality in the plane, originally posed by Maz'ya [Problem 1, Integral Equations Operator Theory, 2018]. More precisely, we show that, for any given $s\in(0,1)$ and any bounded domain $Ω\subset \mathbb{R}^2$ with $C^1$ boundary, $$ P_s(Ω) \le \frac{π^{s-\frac{1}{2}}Γ\left(\frac{3-s}{2}\right)}{s(1-s)Γ\left(\frac{4-s}{2}\right)}\left[\mathcal{H}^1(\partialΩ)\right]^{2-s}, $$ where $P_s$ denotes the fractional $s$-perimeter, $Γ$ denotes the Gamma function, and $\mathcal{H}^{1}$ denotes the $1$-dimensional Hausdorff measure on $\mathbb{R}^2$. The constant is sharp and equality is attained by the disk. The proof proceeds in three steps: reducing the fractional perimeter to a chord functional, reducing connected domains to convex bodies, and proving the sharp convex chord inequality via a fractional Willmore-type inequality, a variational formula along outer parallel bodies, and asymptotic analysis.

math.FA↗

Norms of the Hilbert Matrix Operator on Some Analytic Function Spaces

For $\mathcal H:\mathcal B^α\to\mathcal B^α$ with $1<α<2$, we obtain an exact norm representation. In particular, the norm is given by an explicit Gamma-function formula for $1<α\leq3/2$, whereas for $3/2<α<2$ it strictly exceeds the corresponding Gamma-function expression. For $\mathcal H:\mathcal B^α\to\mathcal B^α_{\log}$, we determine the exact norm: it is equal to $3/2$ for $1<α\leq4/3$ and is given by an explicit Gamma-function formula for $4/3<α<2$. We also determine the exact norm of $\mathcal H:H^1\to H^1_{\log}$ and show that it is equal to $π$. Finally, for $0<α<1$, we determine the exact norm of $\mathcal H:H^\infty_α\to\mathcal B^{α+1}$, which is given by an explicit Gamma-function formula.

math.FA↗

Second quantization and compactness of induced Gaussian quantum Markov semigroups

We characterize compactness of the Hilbert-Schmidt semigroups induced by finite-mode Gaussian quantum Markov semigroups with a faithful normal invariant state. A unitary second-quantization representation for every $ s $-embedding shows that compactness at one positive time, compact resolvent, drift stability, and uniqueness of the normal invariant state are equivalent. These conditions imply immediate trace-class membership for all embeddings. We derive exact trace-norm and Hilbert-Schmidt norm formulas, an embedding-independent trace identity, and the generator spectrum with algebraic multiplicities. Examples show that compactness does not require the existence of a spectral gap and that a spectral gap need not imply compactness when the invariant state is not unique.

math.FA↗