Martin Ohm (May 6, 1792 in

Erlangen Erlangen (; , ) is a Middle Franconian city in Bavaria, Germany. It is the seat of the administrative district Erlangen-Höchstadt (former administrative district Erlangen), and with 119,810 inhabitants (as of 30 September 2024), it is the smalle ...

– April 1, 1872 in

Berlin Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population withi ...

) was a German

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, mathematical structure, structure, space, Mathematica ...

and a younger brother of

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

Georg Ohm Georg Simon Ohm (; ; 16 March 1789 – 6 July 1854) was a German mathematician and physicist. As a school teacher, Ohm began his research with the new electrochemical cell, invented by Italian scientist Alessandro Volta. Using equipment of his o ...

Biography

He earned his doctorate in 1811 at Friedrich-Alexander-University, Erlangen-Nuremberg where his advisor was Karl Christian von Langsdorf. In 1817, he was appointed professor of mathematics and physics in the gymnasium at Thorn. In 1821 he moved to Berlin, and in 1839 became a full professor in the

University of Berlin The Humboldt University of Berlin (, abbreviated HU Berlin) is a public research university in the central borough of Mitte in Berlin, Germany. The university was established by Frederick William III on the initiative of Wilhelm von Humbol ...

. He delivered courses of lectures at the academy of architecture from 1824 to 1831, and at the schools of artillery and engineering from 1833 to 1852; and he also taught in the military school from 1826 to 1849.

Work

Ohm was the first to fully develop the theory of the

exponential Exponential may refer to any of several mathematical topics related to exponentiation, including: * Exponential function, also: **Matrix exponential, the matrix analogue to the above *Exponential decay, decrease at a rate proportional to value * Ex ...

''a''^''b'' when both ''a'' and ''b'' are

complex number In mathematics, a complex number is an element of a number system that extends the real numbers with a specific element denoted , called the imaginary unit and satisfying the equation i^= -1; every complex number can be expressed in the for ...

s in 1823. The 1835 second edition of Ohm's textbook, ''Die reine Elementar Mathematik'' was the first time that Euclid's 'extreme and mean ratio' was given the name of the "

golden section In mathematics, two quantities are in the golden ratio if their ratio is the same as the ratio of their summation, sum to the larger of the two quantities. Expressed algebraically, for quantities and with , is in a golden ratio to if \fr ...

" (''goldener Schnitt''). It was via sources relying on Ohm that the psychologist Adolf Zeising adopted and popularised the term.

Students

Ohm's students included Friedrich August, Friedrich Bachmann,

Elwin Bruno Christoffel Elwin Bruno Christoffel (; 10 November 1829 – 15 March 1900) was a German mathematician and physicist. He introduced fundamental concepts of differential geometry, opening the way for the development of tensor calculus, which would later provid ...

, Paul Bachmann, Joseph Brutkowski, Heinrich Eduard Heine,

Rudolf Lipschitz Rudolf Otto Sigismund Lipschitz (14 May 1832 – 7 October 1903) was a German mathematician who made contributions to mathematical analysis (where he gave his name to the Lipschitz continuity condition) and differential geometry, as well as numbe ...

, Leo Pochhammer,

Friedrich Prym Friedrich Emil Fritz Prym (28 September 1841, Düren – 15 December 1915, Bonn) was a German mathematician who introduced Prym varieties and Prym differentials. Prym completed his Ph.D. at the Humboldt University of Berlin, University of Berli ...

, Wilhelm Wagner, Hermann Waldaestel, Wilhelm Wernicke, Elena Gerz, Valentien Gerz, and Johanna Gerz.

Selected publications

* ''Die reine Elementar Mathematik (Pure elementary mathematics).'' Berlin, 1825; second edition 1835. * ''Kurzes Elementar-Lehrbuch der gesammten mechanischen Wissenschaften für höhere Bürger-, technische, Gewerb- und Militär-Schule''n. Berlin, 1840. * ''Aufsätze aus dem Gebiete der höhern Mathematik'' * ''Die analytische und höhere Geometrie in ihren Elementen mit vorzüglicher Berücksichtigung der Theorie der Kegelschnitte,'' Berlin Riemann 1826 * ''Versuch eines vollkommen consequenten Systems der Mathematik''. Nürnberg, F. Korn, 1853-55. * Lehrbuch der Mechanik zugleich mit den dazu nöthigen Lehren der höhern Analysis und der höhern Geometrie 1 Mechanik des Atoms. Berlin Enslin 1836

References

{{DEFAULTSORT:Ohm, Martin 19th-century German mathematicians 1792 births 1872 deaths Academic staff of the Humboldt University of Berlin Georg Ohm