A Cheeger-type Inequality for the Sub-Laplacian on Pseudo-Hermitian CR Manifolds. European Journal of Pure and Applied Mathematics, Maryland, USA, v. 18, n. 4, p. 6985, 2025. DOI: 10.29020/nybg.ejpam.v18i4.6985. Disponível em: https://www.ejpam.com/index.php/ejpam/article/view/6985. Acesso em: 5 dec. 2025.