Concerning the theorem of Ferrand-Obata
The authors give a new proof of the following known fact: The group \(\operatorname {Conf}(M)\) of all conformal transformations of a Riemannian manifold \(M\) is essential iff \(M\) is conformally equivalent to either \(S^n\) or \(\mathbb R^n\). The methods of their proof allow them to obtain another result: If a foliation \(\mathcal F\) of a compact manifold \(M\) is transversally conformal, \(\operatorname {codim}{\mathcal F}\geq 3\) and all the basic functions of \(\mathcal F\) are constant, then \(\mathcal F\) is either Riemannian or transversally Möbius.
scientific article; zbMATH DE number 1747788