Electronic Journal of Differential Equations, Vol. 2025 (2025), No. 18, pp. 1-40. Title: Quantitative estimates of L^p maximal regularity for nonautonomous operators and global existence for quasilinear equations Authors: Theo Belin (Univ. Paris-Saclay, France) Pauline Lafitte (Univ. Paris-Saclay, France) Abstract: In this work, we obtain quantitative estimates of the continuity constant for the $L^p$ maximal regularity of relatively continuous nonautonomous operators $A : I \to \mathcal{L}(D,X)$, where $D \hookrightarrow X$ densely and compactly. They allow in particular to establish a new general growth condition for the global existence of strong solutions of Cauchy problems for nonlocal quasilinear equations for a certain class of nonlinearities $u \mapsto \mathbb{A}(u)$. The estimates obtained rely on the precise asymptotic analysis of the continuity constant with respect to perturbations of the operator of the form $A(\cdot) + \lambda \text{Id}$ as $\lambda \to \pm \infty$. A complementary work in preparation supplements this abstract inquiry with an application of these results to nonlocal parabolic equations in noncylindrical domains depending on the time variable. Submitted October 8, 2024. Published February 26, 2025 Math Subject Classifications: 35K90, 35K59, 35D35, 47D06. Key Words: Nonautonomous Cauchy problem; $L^p$ maximal regularity; relatively continuous operators; quasilinear equations.