See also: Steiner

Jakob Steiner born the March 18th 1796 and dead on April 1st 1863, is a mathematician Suisse.

It was born in the village from Utzendorf, Canton of Bern. At eighteen years, he became a pupil of Heinrich Pestalozzi, and then studied with Heidelberg. He then went to Berlin, earning his living, as in Heidelberg, by giving private lessons. He then became acquainted with Crelle, which, encouraged by its capacities and those of Abel, then also in Berlin, founded its famous newspaper (1826).

After the publication (1832) of sound Systematische Entwickelungen , it received, thanks to the support of Charles Gustave Jacob Jacobi, which was then professor with Königsberg, an honorary diploma of this university. Under the influence of G.J. Jacobi and Alexander brothers and Wilhelm von Humboldt, a new pulpit of geometry was founded for him in Berlin in 1834. It occupied this station until its death, which took place in Bern on April 1st 1863.

The mathematical work of Steiner is primarily geometrical. In its own field it exceeded all its contemporaries. Its research is characterized by their great general information and such a rigor in its evidence that he was regarded as the greatest geometrical genius since the time of Apollonius.

In its Systematische Entwickelung der Abhängigkeit geometrischer Gestalten von einander , it created the bases of the synthetic Géométrie modern. In this book also, whose unfortunately only one volume is appeared on the five laid down, one finds for the first time the principle of duality presented as of the beginning like immediate consequence of the most fundamental properties of the plan, the line and the point.

In a second little book Die geometrischen Constructionen ausgeführt mittels DER geraden Linie und eines festen Kreises (1833), republished in 1895 by Ottingen, it shows, which had been already suggested by J.V. Poncelet, how all the second-order problems can be solved using the rule only and without use of the compass, since a circle is given on paper. He also wrote " Vorlesungen über synthetische Geometrie", published in a posthumous way in Leipzig by c.f. Geiser and H. Schroeter in 1867; a third edition by R. Sturm was published in 1887 - 1898.

The remainder of works of Steiner is in many reviews, often with the newspaper of Crelle, whose first volume contains its first four papers. Most important are those concerning the curves and the algebraic surfaces, particularly the short article Allgemeine Eigenschaften algebraischer Curven (general Properties of the algebraic curves). This one contains only results, and there is no indication of the method by which they were obtained, so that, according to L.O. Hosse, they are, like the Dernier theorem of Fermat, of the enigmas to the generations present and future. Eminent analysts succeeded in showing some of the theorems, but L was needed. Casement bolt to show them all, by a uniform synthetic method, in its book on the algebraic curves. Other important research is related to the maximum and the minimum.

The articles of Steiner were gathered and published in two volumes (Gesammelte Werke, 1881-1882) by the Académie of Berlin.

See also

• Tree of Steiner
• Surface of Steiner
• Theorem of Poncelet-Steiner