Best Constants for Anisotropic Moser-Trudinger Inequalities with the Exact Growth Condition and Their Applications

Abstract: We investigate the best constants associated with several types of Moser--Trudinger inequalities within the framework of the Finsler metric in $\mathbb{R}<sup>n$. By employing a convex-symmetrization-free approach, we first establish both the critical and subcritical anisotropic singular Moser--Trudinger inequalities. We further study anisotropic Moser--Trudinger inequalities in both singular and nonsingular cases under the exact growth condition, highlighting the optimality of the best constant as well as the sharp exponent appearing in the denominator. To further enrich the theory, we introduce quasi-conformal-type transformations adapted to the Finsler metric setting to derive several new variants of such inequalities. We also characterize the attainability and nonattainability of maximizers for a generalized version of anisotropic Moser--Trudinger inequalities with the exact growth and explicitly determine the corresponding supremum values. As an application of these inequalities, we analyze the existence and nonexistence of positive ground state solutions to a class of $n$-Finsler-Laplace equations involving constant potential in $\mathbb{R}<sup>n$, where the nonlinearity exhibits a critical exponential growth at infinity.