Fourier integral operators on Orlicz modulation spaces
Serap Öztop, Rüya Üster, Joachim Toft
TL;DR
This work extends the theory of Fourier integral operators to the Orlicz modulation space setting, addressing operators with non-smooth amplitudes and phases. By placing amplitudes in $M^{\infty,1}_{(\omega)}$ and phases in $M^{\infty,1}_{(v)}$ under a nondegeneracy condition, it proves continuity on a wide class of Orlicz modulation spaces $M^{\Phi}_{(\omega)}$, including cases where $\Phi$ encodes Lebesgue-type norms. It then develops Schatten-von Neumann results for FIOs by analyzing kernels in Orlicz modulation spaces and establishing $\operatorname{Op}_\varphi(a) \in \mathscr I_{\Phi}(\omega_1,\omega_2)$, with extensions to kernel-based and $A$-modified FIOs. Overall, the paper broadens the applicability of FIOs to non-Lebesgue environments, enabling fine-grained analysis under subexponential weights and general Young functions, with potential impact on hyperbolic-type problems and related PDE analysis.
Abstract
We establish continuity and Schatten-von Neumann properties for Fourier integral operators with amplitudes in Orlicz modulation spaces, when acting on other Orlicz modulation spaces themselves. The phase functions are non smooth and admit second order derivatives in suitable classes of modulation spaces.
