Alfred Aeppli was a Swiss mathematician. The

Pólya–Aeppli distribution In probability theory and statistics, the geometric Poisson distribution (also called the Pólya–Aeppli distribution) is used for describing objects that come in clusters, where the number of clusters follows a Poisson distribution and the number ...

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 o ...

and

statistics Statistics (from German language, German: ''wikt:Statistik#German, Statistik'', "description of a State (polity), state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of ...

is named after him and his doctoral advisor

George Pólya George Pólya (; hu, Pólya György, ; December 13, 1887 – September 7, 1985) was a Hungarian mathematician. He was a professor of mathematics from 1914 to 1940 at ETH Zürich and from 1940 to 1953 at Stanford University. He made fundamental ...

Life and work

Alfred Aeppli was born in

Zürich Zürich () is the list of cities in Switzerland, largest city in Switzerland and the capital of the canton of Zürich. It is located in north-central Switzerland, at the northwestern tip of Lake Zürich. As of January 2020, the municipality has 43 ...

on 15 July 1894 to Alfred Aeppli and Rosa Aeppli-Gehring. He went to a primary school in Zürich and the

canton Canton may refer to: Administrative division terminology * Canton (administrative division), territorial/administrative division in some countries, notably Switzerland * Township (Canada), known as ''canton'' in Canadian French Arts and ent ...

's Industrial School, where he received his

matura or its translated terms (''Mature'', ''Matur'', , , , , , ) is a Latin name for the secondary school exit exam or "maturity diploma" in various European countries, including Albania, Austria, Bosnia and Herzegovina, Bulgaria, Croatia, Czech ...

in the summer of 1913. Afterwards, Aeppli studied at the

Eidgenössische Technische Hochschule (colloquially) , former_name = eidgenössische polytechnische Schule , image = ETHZ.JPG , image_size = , established = , type = Public , budget = CHF 1.896 billion (2021) , rector = Günther Dissertori , president = Joël Mesot , ac ...

(ETH Zürich) at the department for higher teachers of mathematics and physics. In the winter semester of 1914–1915 he was on leave for military service. After receiving his

Diplom A ''Diplom'' (, from grc, δίπλωμα ''diploma'') is an academic degree in the German-speaking countries Germany, Austria, and Switzerland and a similarly named degree in some other European countries including Albania, Bulgaria, Belarus ...

, he worked at a private school in Germany for a year and returned to the ETH in the spring of 1919 as a research assistant of

Arthur Hirsch Arthur Hirsch (1866–1948) was a German mathematician. Life and work Hirsch completed his schooling in Königsberg in 1882 and then studied mathematics and physics in the universities of Berlin and Königsberg. Among his teachers at Königs ...

. Aeppli earned his doctorate in 1924 under the supervision of George Pólya and

Hermann Weyl Hermann Klaus Hugo Weyl, (; 9 November 1885 – 8 December 1955) was a German mathematician, theoretical physicist and philosopher. Although much of his working life was spent in Zürich, Switzerland, and then Princeton, New Jersey, he is assoc ...

. He came up with the Pólya–Aeppli distribution in his doctoral dissertation. This discovery was published by Pólya in 1930, and he credited its discovery to his student Aeppli. The Pólya–Aeppli distribution, now also known as the geometric Poisson distribution, is a particular case of the

compound Poisson distribution In probability theory, a compound Poisson distribution is the probability distribution of the sum of a number of independent identically-distributed random variables, where the number of terms to be added is itself a Poisson-distributed variable. T ...

, and is used to describe objects that come in clusters, where the number of clusters follows a

Poisson distribution In probability theory and statistics, the Poisson distribution is a discrete probability distribution that expresses the probability of a given number of events occurring in a fixed interval of time or space if these events occur with a known co ...

and the number of objects within a cluster follows a

geometric distribution In probability theory and statistics, the geometric distribution is either one of two discrete probability distributions: * The probability distribution of the number ''X'' of Bernoulli trials needed to get one success, supported on the set \; * ...

References

{{DEFAULTSORT:Aeppli, Alfred 20th-century Swiss mathematicians ETH Zurich alumni Probability theorists 1894 births Year of death missing Scientists from Zürich