Aleksandr Petrovich Kotelnikov (1865 – 1944) was a Russian mathematician specializing in geometric algebra. Kotelnikov graduated from Kazan University in 1884 and began teaching at a gymnasium. He began graduate work in mechanics and started instructing at the university in 1893. For his doctorate in 1899 he wrote on the projective theory of vectors. As an advocate of the quaternions, Kotelnikov represented the Quaternion Society in Russia. He moved to Kiev where he was professor and head of the department of pure mathematics until 1904. Returning to Kazan, he headed the mathematics department until 1914. He was at the Kiev Polytechnic Institute directing the department of Theoretical Mechanics until 1924, when he moved to Moscow and took up teaching at Bauman Technical University.
Nikolai Lobachevsky was a colleague of P.I. Kotelnikov, Aleksandr's father. Since Lobachevky's contribution to geometry, namely hyperbolic geometry, was so unorthodox, it was widely dismissed, but not by P.I Kotelnikov who publicly praised the innovation. Aleksandr organized the publication of Lobachevsky's writings after his death. He was also the editor of the collected works of Nikolai Zhukovsky, the father of Russian aerodynamics.