Strichartz Estimates for the Vibrating Plate Equation

We study the dispersive properties of the linear vibrating plate (LVP) equation. Splitting it into two Schr\"odinger-type equations we show its close relation with the Schr\"odinger equation. Then, the homogeneous Sobolev spaces appear to be the natural setting to show Strichartz-type estimates for the LVP equation. By showing a Kato-Ponce inequality for homogeneous Sobolev spaces we prove the well-posedness of the Cauchy problem for the LVP equation with time-dependent potentials. Finally, we exhibit the sharpness of our results. This is achieved by finding a suitable solution for the stationary homogeneous vibrating plate equation.Comment: 18 pages, 4 figures, some misprints correcte

Geodesic Completeness for Sobolev Metrics on the Space of Immersed Plane Curves

We study properties of Sobolev-type metrics on the space of immersed plane curves. We show that the geodesic equation for Sobolev-type metrics with constant coefficients of order 2 and higher is globally well-posed for smooth initial data as well as initial data in certain Sobolev spaces. Thus the space of closed plane curves equipped with such a metric is geodesically complete. We find lower bounds for the geodesic distance in terms of curvature and its derivatives

Caffarelli-Kohn-Nirenberg inequalities on Besov and Triebel-Lizorkin-type spaces

We present some Caffarelli-Kohn-Nirenberg-type inequalities on Herz-type Besov-Triebel-Lizorkin spaces, Besov-Morrey spaces and Triebel-Lizorkin-Morrey spaces. More Precisely, we investigate the inequalities \begin{equation*} \big\|f\big\|_{\dot{k}_{v,\sigma }^{\alpha _{1},r}}\leq c\big\|f\big\|_{\dot{K}_{u}^{\alpha _{2},\delta }}^{1-\theta }\big\|f\big\|_{\dot{K}_{p}^{\alpha _{3},\delta _{1}}A_{\beta }^{s}}^{\theta }, \end{equation*} and \begin{equation*} \big\|f\big\|_{\mathcal{E}_{p,2,u}^{\sigma }}\leq c\big\|f\big\|_{\mathcal{M}_{\mu }^{\delta }}^{1-\theta }\big\|f\big\|_{\mathcal{N}_{q,\beta ,v}^{s}}^{\theta }, \end{equation*} with some appropriate assumptions on the parameters, where $\dot{k}_{v,\sigma }^{\alpha _{1},r}$ is the Herz-type Bessel potential spaces, which are just the Sobolev spaces if $\alpha _{1}=0,1<r=v<\infty$ and $\mathbb{N}_{0}$, and $\dot{K}_{p}^{\alpha _{3},\delta _{1}}A_{\beta }^{s}$ are Besov or Triebel-Lizorkin spaces if $\alpha _{3}=0$ and$\ \delta _{1}=p$. To do these, we study when distributions belonging to these spaces can be interpreted as functions in $L_{\mathrm{loc}}^{1}$. The usual Littlewood-Paley technique, Sobolev and Franke embeddings, and interpolation theory are the main tools of this paper. Some remarks on Hardy-Sobolev inequalities are given.Comment: We add Subsection 3.4, Propositions 1-3, Theorem 9 and Appendi