Comment: Towards a complete classification of spherically symmetric Lorentzian manifolds according to their Ricci collineations (Q1874744)

In this paper the author studies in detail the solution of Ricci collineations equation for spherically symmetric Lorentzian manifolds. A general solution is given for a non-degenerate or degenerate cases. Some examples are used for the results given in references [\textit{J. Carot}, \textit{L. Nuñez} and \textit{U. Percoco}, Gen. Relativ. Gravitation 29, 1223--1237 (1997; Zbl 0896.53042); \textit{G. Contreras, L. A. Núñez} and \textit{U. Percoco}, Gen. Relativ. Gravit. 32, 285--294 (2000; Zbl 0995.53015);\textit{U. Camci} and \textit{A. Banes}, Classical Quantum Gravity 19, No. 2, 393--404 (2002)].