German mathematician; born Feb. 22, 1817, at Berlin; died there June 27, 1880. He studied from 1839 to 1843 at Königsberg, where Jacobi exerted a great influence on him. He passed the winter of 1846-47 at Paris, where he continued his mathematical studies under Lionville; and in 1848 he became privat-docent at the University of Berlin. In 1856 the Berlin Academy of Sciences elected him a member. After the death of Crelles, Borchardt became editor of the "Journal für die Reine und Angewandte Mathematik." A complete edition of his works was published by the Berlin Academy of Sciences under the direction of G. Hettner, Berlin, 1888.