George Adam Pfeiffer (16 July 1889, New York City – 28 December 1943) was an American mathematician. Pfeiffer received in 1910 his master's degree in engineering from

Stevens Institute of Technology Stevens Institute of Technology is a private research university in Hoboken, New Jersey. Founded in 1870, it is one of the oldest technological universities in the United States and was the first college in America solely dedicated to mechanical ...

and then his A.M. in 1911 and in 1914 his Ph.D. in mathematics from

Columbia University Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...

. He spent the academic year 1914–1915 as a Benjamin Pierce Instructor at Harvard University and then in 1915 became an instructor at

Princeton University Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...

. During WW I, he was in the U.S. army and at Princeton University taught meteorology to army aviation students. After the war he taught, starting as an instructor in February 1919, at Columbia University. There he became in 1924 an assistant professor and in 1931 an associate professor, in which position he remained until his death from a heart attack following minor surgery in 1943. Pfeiffer is known for publishing the first example of a holomorphic function with a non-linearizable irrational indifferent fixed point. The question of the linearizability of fixed points is of great importance in

complex dynamics Complex dynamics is the study of dynamical systems defined by Iterated function, iteration of functions on complex number spaces. Complex analytic dynamics is the study of the dynamics of specifically analytic functions. Techniques *General **Mo ...

. After Pfeiffer's example, Hubert Cremer gave various criteria for the non-linearizability of irrational indifferent fixed points, while

Carl Ludwig Siegel Carl Ludwig Siegel (31 December 1896 – 4 April 1981) was a German mathematician specialising in analytic number theory. He is known for, amongst other things, his contributions to the Thue–Siegel–Roth theorem in Diophantine approximation, ...

in 1942 gave conditions which imply the linearizability of such fixed points.A description and discussion of the results of Pfeiffer, Cremer and Siegel are available in the book by Alexander, Iavernaro and Rosa. Pfeiffer was on the editorial staff of

Annals of Mathematics The ''Annals of Mathematics'' is a mathematical journal published every two months by Princeton University and the Institute for Advanced Study. History The journal was established as ''The Analyst'' in 1874 and with Joel E. Hendricks as the ...

Sources

* Daniel Alexander, Felice Iavernaro, Alessandro Rosa
''Early days in complex dynamics: a history of complex dynamics in one variable 1906-1940''
History of Mathematics 38, American Mathematical Society 2012; biography of Pfeiffer on p. 365

Selected publications

"On the conformal geometry of analytic arcs."
American Journal of Mathematics 37, no. 4 (1915): 395–430. * "Note on the linear dependence of analytic functions." Bulletin of the American Mathematical Society 23, no. 3 (1916): 117–118. * "A property of the level lines of a region with a rectifiable boundary." Bulletin of the American Mathematical Society 34, no. 5 (1928): 656–664.

References

{{DEFAULTSORT:Pfeiffer, George Adam 1889 births 1943 deaths 20th-century American mathematicians Stevens Institute of Technology alumni Columbia Graduate School of Arts and Sciences alumni Columbia University faculty