On a class of hypersurfaces of a product of two space forms
Arnando Carvalho, Ruy Tojeiro
Abstract
We define hypersurfaces $f\colon M^n\to \mathbb{Q}_{c_1}^{k} \times \mathbb{Q}_{c_2}^{n-k+1}$ in class $\mathcal{A}$ of a product of two space forms as those that have flat normal bundle when regarded as submanifolds of the underlying flat ambient space. We provide an explicit construction of them in terms of parallel families of hypersurfaces of the factors. We show that hypersurfaces with constant mean curvature in class $\mathcal{A}$ are given in terms of parallel families of isoparametric hypersurfaces in each factor and a solution of a second order ODE. Finally, we classify hypersurfaces with constant mean curvature in class $\mathcal{A}$ that have constant product angle function.
