Über das Zentrum metrischer Bewegungsgruppen nach Ewald
Let G be a group of motion in a metric geometry in the sense of \textit{G. Ewald} [Abh. math. Sem. Univ. Hamb. 41, 224-251 (1975; Zbl 0287.50001)]. It is given a condition (admitting a geometric interpretation) which implies the triviality of the center of G.
scientific article; zbMATH DE number 3861922