# Moving and oblique observations of beams and plates

## TL;DR

This paper investigates how moving or oblique observations affect the ability to observe beams, plates, and Schrödinger equations, using Fourier series techniques to establish observability and non-observability results.

## Contribution

It introduces new observability theorems for beams, plates, and Schrödinger equations under moving and oblique observation conditions, extending existing theoretical frameworks.

## Key findings

- Established conditions for observability with moving observations
- Identified scenarios where observability fails under certain conditions
- Formulated open problems for future research in observation theory

## Abstract

We study the observability of the one-dimensional Schr{\"o}dinger equation and of the beam and plate equations by moving or oblique observations. Applying different versions and adaptations of Ingham's theorem on nonharmonic Fourier series, we obtain various observability and non-observability theorems. Several open problems are also formulated at the end of the paper.