Virginia Ragsdale

Virginia Ragsdale ( born December 13, 1870 in Jamestown, North Carolina, † June 4, 1945 ) was an American mathematician who made ​​important contributions to the solution of Hilbert's 16th problem returned.

Ragsdale grew up on a farm and graduated from Salem Academy and at Guilford College in Greensboro. After the bachelor's degree in 1892, she went with a scholarship to the Bryn Mawr College, which was followed by a year at the University of Göttingen with Felix Klein and David Hilbert also obtained thanks to a scholarship. After that, she taught at the Bryn Mawr School in Baltimore, before returning to the Bryn Mawr College, where she was his doctorate in 1906. The dissertation ( at Charlotte Angas Scott) was based on work in Göttingen in Hilbert and was her only publication. 1911 to 1928 she was a professor at the Woman's College of North Carolina at Greensboro (now the University of North Carolina at Greensboro ). 1926-1928 she stood in front of the faculty.

Ragsdale turned to in her thesis ( as the same time, several other students of Hilbert's ) the real algebraic geometry and especially the 16th problem of Hilbert, which asks for the number and arrangement of ovals and branches of real algebraic curves given level. In particular, they examined real curves with even degree and discovered that the difference pn the number of even and odd ovals ( ie with an even or odd number of other ovals within each oval ) is a topological invariant (the Euler characteristic of the Oval limited area ). In their work, they formulated some conjectures about one ( depending on the degree of the curve) upper limit to the number of even and odd ovals of a curve of degree 2k, which were refuted in 1979 by Oleg Wiro and 1994 by Ilia Itenberg. The problem, the precise upper limits exist instead, is open.