Outer space
Karen Vogtmann (born July 13, 1949, in Pittsburg, California) is an American mathematician working primarily in the area of geometric group theory. She is known for having introduced, in a 1986 paper with Marc Culler, an object now known as the Culler–Vogtmann Outer space. The Outer space is a free group analog of the Teichmüller space of a Riemann surface and is particularly useful in the study of the group of outer automorphisms of the free group on "n" generators, Out("F""n"). Vogtmann is a professor of mathematics at Cornell University and The University of Warwick.