Frank Ludvig Spitzer (July 24, 1926 – February 1, 1992) was an

Austrian Austrian may refer to: * Austrians, someone from Austria or of Austrian descent ** Someone who is considered an Austrian citizen, see Austrian nationality law * Austrian German dialect * Something associated with the country Austria, for example: ...

-born American

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

who made fundamental contributions to

probability theory Probability theory is the branch of mathematics concerned with probability. Although there are several different probability interpretations, probability theory treats the concept in a rigorous mathematical manner by expressing it through a set ...

, including the theory of

random walk In mathematics, a random walk is a random process that describes a path that consists of a succession of random steps on some mathematical space. An elementary example of a random walk is the random walk on the integer number line \mathbb Z ...

s, fluctuation theory,

percolation theory In statistical physics and mathematics, percolation theory describes the behavior of a network when nodes or links are added. This is a geometric type of phase transition, since at a critical fraction of addition the network of small, disconnecte ...

, the

Wiener sausage In the mathematical field of probability, the Wiener sausage is a neighborhood of the trace of a Brownian motion up to a time ''t'', given by taking all points within a fixed distance of Brownian motion. It can be visualized as a sausage of fixe ...

, and especially the

theory A theory is a rational type of abstract thinking about a phenomenon, or the results of such thinking. The process of contemplative and rational thinking is often associated with such processes as observational study or research. Theories may be ...

interacting particle system In probability theory, an interacting particle system (IPS) is a stochastic process (X(t))_ on some configuration space \Omega= S^G given by a site space, a countable-infinite graph G and a local state space, a compact metric space S . More ...

s. Rare among mathematicians, he chose to focus broadly on " phenomena", rather than any one of the many specific

theorem In mathematics, a theorem is a statement that has been proved, or can be proved. The ''proof'' of a theorem is a logical argument that uses the inference rules of a deductive system to establish that the theorem is a logical consequence of t ...

s that might help to articulate a given phenomenon. His book ''Principles of Random Walk'', first published in 1964, remains a well-cited classic. Spitzer was born into a

Jew Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""T ...

ish family in

Vienna en, Viennese , iso_code = AT-9 , registration_plate = W , postal_code_type = Postal code , postal_code = , timezone = CET , utc_offset = +1 , timezone_DST ...

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

, and by the time he was twelve years old, the

Nazi Nazism ( ; german: Nazismus), the common name in English for National Socialism (german: Nationalsozialismus, ), is the far-right totalitarian political ideology and practices associated with Adolf Hitler and the Nazi Party (NSDAP) in ...

threat in Austria was evident. His parents were able to send him to a

summer camp A summer camp or sleepaway camp is a supervised program for children conducted during the summer months in some countries. Children and adolescents who attend summer camp are known as ''campers''. Summer school is usually a part of the academ ...

for Jewish children in Sweden, and, as a result, Spitzer spent all of the war years in Sweden. He lived with two Swedish families, learned

Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...

, graduated from high school, and for one year attended Tekniska Hogskolan in Stockholm. During the war years, Spitzer's parents and his sister were able to make their way to the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

by passing through the unoccupied parts of

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...

and

North Africa North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...

, and, after the war, Spitzer joined his family in their new country. Spitzer enlisted in the

U.S. Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cl ...

just as the war in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

was ending. After completing his

military service Military service is service by an individual or group in an army or other militia, air forces, and naval forces, whether as a chosen job ( volunteer) or as a result of an involuntary draft (conscription). Some nations (e.g., Mexico) require ...

in 1947, Spitzer entered the

University of Michigan , mottoeng = "Arts, Knowledge, Truth" , former_names = Catholepistemiad, or University of Michigania (1817–1821) , budget = $10.3 billion (2021) , endowment = $17 billion (2021)As o ...

( Ann Arbor) to study mathematics. His studies went quickly, and he completed his B.A. and Ph.D. in just six years. Spitzer's first academic appointments were at the

California Institute of Technology The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...

(1953–1958), but most of his academic career was spent at

Cornell University Cornell University is a private statutory land-grant research university based in Ithaca, New York. It is a member of the Ivy League. Founded in 1865 by Ezra Cornell and Andrew Dickson White, Cornell was founded with the intention to tea ...

, with leaves at the Institute for Advanced Study in

Princeton Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the ni ...

and the Mittag-Leffler Institute in Sweden. Among his many honors, Spitzer was a member of the National Academy of Sciences.

Publications

References

External links

*
Harry Kesten, "Frank Ludvig Spitzer", Biographical Memoirs of the National Academy of Sciences (1996)
{{DEFAULTSORT:Spitzer, Frank 1926 births 1992 deaths Austrian mathematicians American people of Austrian-Jewish descent 20th-century American mathematicians University of Michigan College of Literature, Science, and the Arts alumni KTH Royal Institute of Technology alumni Probability theorists Members of the United States National Academy of Sciences