. . "1921-04-17Z"^^ . "2017-04-08Z"^^ . . . "Chike Obi (April 17, 1921 \u2013 March 13, 2008) was a Nigerian politician, mathematician and professor.The African Mathematics Union suggests that he was the first sub-Saharan African to hold a doctorate in mathematics. Dr. Obi's early research dealt mainly with the question of the existence of periodic solutions of non-linear ordinary differential equations."@en . . "2008-03-13Z"^^ . "2008Z"^^ . . "Nigerianmathematician" . "1921Z"^^ . "Chike Obi"@en . .