. . . . "1849Z"^^ . . . "Klein, Felix"@en . "1925-06-22Z"^^ . . . "Felix Klein"@en . . . . . . "Christian Felix Klein (25 April 1849 \u2013 22 June 1925) was a German mathematician and mathematics educator, known for his work in group theory, complex analysis, non-Euclidean geometry, and on the connections between geometry and group theory. His 1872 Erlangen Program, classifying geometries by their underlying symmetry groups, was a hugely influential synthesis of much of the mathematics of the day."@en . . . . . . . . . . "Mathematician" . "1849-04-25Z"^^ . . "1925Z"^^ .