3 papers
math.AP2026
Fifty Years of Wave Equations with Time-Dependent Propagation Speeds: A Variational Perspective and New Frontiers
Marina Ghisi, Massimo Gobbino
We study abstract wave equations with time-dependent propagation speed under strict hyperbolicity. Our starting point is the observation that a substantial part of the classical en…
math.AP2025
The model example of wave equation with oscillating scale-invariant damping
Marina Ghisi, Massimo Gobbino
We analyze a simple example of wave equation with a time-dependent damping term, whose coefficient decays at infinity at the scale-invariant rate and includes an oscillatory compon…
math.AP2024
Generalized energy conservation for linear wave equations with time-dependent propagation speed
Marina Ghisi, Massimo Gobbino
We consider a wave equation with a time-dependent propagation speed, whose potential oscillations are controlled through bounds on its first and second derivatives and by limiting…