### Len Berggren

##### Research Interests

Most of my work centers on the study of the mathematical sciences in ancient Greece and medieval Islam, and I am presently publishing, with a colleague at Toronto, a translation of the theoretical portions of Ptolemy's Geography that are not simply lists of coordinates of geographic localities. This work was an inspiration to geographers of the Islamic middle ages and during the heyday of European discovery of new worlds, and contains a variety of mathematical methods in geography and cartography, but up to the present has received no satisfactory English translation. I am also engaged in the translation and study of the geometrical works of the 10th century Persian Scientist, Abu Sahl al-Kuhi. These works continue the Greek geometric heritage of rigorous solution of difficult problems, found in Archimedes and Apollonius, and among his major works are studies of centers of gravity, the geometry of astrolables, and the construction of a geometrical compass for drawing conic sections.