| Hermann Grassmann |
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| 1809 births | |
| 1877 deaths | |
| 19th century mathematicians | |
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BIOGRAPHY Hermann Grassmann was the third of 12 children of Justus Günter Grassmann, an ordained minister who taught mathematics and physics at the Stettin Gymnasium , where Hermann was educated. Hermann often collaborated with his brother Robert. This entry dwells on the details of Grassman's career more than usual, because his mathematical work was not recognized in his lifetime. Grassmann was an undistinguished student until he obtained a high mark on the examinations for admission to Prussian universities. Beginning in 1827, he studied Theology at the University Of Berlin , also taking classes in Classical Languages , Philosophy , and literature; he does not appear to have taken courses in Mathematics or Physics . Although lacking university training in mathematics, it was the field that most interested him when he returned to Stettin in 1830 after completing his studies in Berlin. After a year of preparation, he sat the examinations needed to teach mathematics in a gymnasium, but achieved a result good enough to allow him to teach only at the lower levels. In the spring of 1832, he was made an assistant at the Stettin Gymnasium. Around this time, he made his first significant mathematical discoveries, ones that led him to the important ideas he set out in his 1844 A1. In 1834 Grassmann began teaching mathematics at the Gewerbeschule in Berlin. A year later, he returned to Stettin to teach mathematics, physics, German, Latin, and religious studies at a new school, the Otto Schule. This wide range of topics reveals again that he was qualified to teach only at a low level. Over the next four years, Grassmann passed examinations enabling him to teach Mathematics , Physics , Chemistry , and Mineralogy at all secondary school levels. Grassmann felt somewhat aggrieved that he was writing innovative mathematics, but taught only in secondary schools. Yet he did rise in rank, even while never leaving Stettin. In 1847, he was made an "Oberlehrer." In 1852, he was appointed to his late father's position at the Stettin Gymnasium, thereby acquiring the title of Professor. In 1847, he asked the Prussian Ministry of Education to be considered for a university position, whereupon that Ministry asked Kummer for his opinion of Grassmann. Kummer wrote back saying that Grassmann's 1846 prize essay (see below) contained "... commendably good material expressed in a deficient form." Kummer's report ended any chance that Grassmann might obtain a university post. This episode proved the norm; time and again, leading figures of Grassmann's day failed to recognize the value of his mathematics. During the political turmoil in Germany, 1848-49, Hermann and Robert Grassmann published a Stettin newspaper calling for German Unification under a Constitutional Monarchy . (This eventuated in 1866.) After writing a series of articles on Constitutional Law , Hermann parted company with the newspaper, finding himself increasingly at odds with its political direction. Grassmann had eleven children, seven of which reached adulthood. A son, Hermann Ernst Grassmann, became a professor of mathematics at the University Of Giessen . MATHEMATICIAN One of then many examination Grassmann sat required that he submit an essay on the theory of the tides. In 1840, he did so, taking the basic theory from Laplace 's ''Méchanique céleste'' and from Lagrange 's ''Méchanique analytique'', but expositing this theory making use of the Vector methods he had been mulling over since 1832. This essay, first published in the ''Collected Works'' of 1894-1911, contains the first known appearance of what are now called Linear Algebra and the notion of a Vector Space . He went on to develop those methods in his A1 and '''A2'''. In 1844, Grassmann published his masterpiece, his ''Die Lineale Ausdehnungslehre, ein neuer Zweig der Mathematik'', hereinafter denoted A1 and commonly referred to as the ''Ausdehnungslehre,'' which translates as "theory of extension" or "theory of extensive magnitudes." Since A1 proposed a new foundation for all of mathematics, the work began with quite general definitions of a philosophical nature. Grassmann then showed that once Geometry is put into the algebraic form he advocated, then the number three has no privileged role as the number of spatial Dimension s; the number of possible dimensions is in fact unbounded. Fearnley-Sander (1979) describes Grassmann's foundation of linear algebra as follows: "The definition of a Linear Space ( Vector Space )... became widely known around 1920, when Hermann Weyl and others published formal definitions. In fact, such a definition had been given thirty years previously by Peano , who was thoroughly acquainted with Grassmann's mathematical work. Grassmann did not put down a formal definition --- the language was not available --- but there is no doubt that he had the concept." "Beginning with a collection of 'units' ''e1, e2, e3, ...'', he effectively defines the free linear space which they generate; that is to say, he considers formal linear combinations ''a1e1 + a2e2 + a3e3 + ...'' where the ''aj'' are real numbers, defines addition and multiplication by real numbers what is now the usual way and formally proves the linear space properties for these operations. ... He then develops the theory of Linear Independence in a way which is astonishingly similar to the presentation one finds in modern linear algebra texts. He defines the notions of Subspace , Independence , Span , Dimension , Join and Meet of subspaces, and Projection s of elements onto subspaces. " "...few have come closer than Hermann Grassmann to creating, single-handedly, a new subject." Following an idea of Grassmann's father, A1 also defined the . (One should keep in mind that in Grassmann's day, the only Axiom atic theory was Euclidian Geometry , and the general notion of an Abstract Algebra had yet to be defined.) In 1878, William Kingdon Clifford joined this exterior algebra to William Rowan Hamilton 's Quaternions by replacing Grassmann's rule ''epep'' = 0 by the rule ''epep'' = 1. For more details, see Exterior Algebra . A1 was a revolutionary text, too far ahead of its time to be appreciated. Grassmann submitted it as a Ph. D. thesis, but Möbius said he was unable to evaluate it and forwarded it to Ernst Kummer , who rejected it without giving it a careful reading. Over the next 10-odd years, Grassmann wrote a variety of work applying his theory of extension, including his 1845 ''Neue Theorie der Elektrodynamik'' and several papers on algebraic curves and surfaces, in the hope that these applications would lead others to take his theory seriously. In 1846, Möbius invited Grassmann to enter a competition to solve a problem first proposed by Leibniz : to devise a geometric calculus devoid of coordinates and metric properties (what Leibniz termed ''analysis situs''). Grassmann's ''Die Geometrische Analyse geknüpft und die von Leibniz Characteristik'', was the winning entry. There was a sting in the tail, however; Grassmann's entry was the only one. Moreover, Möbius, as one of the judges, criticized the way Grassmann introduced abstract notions without giving the reader any intuition as to why those notions were of value. In 1853, Grassmann published a theory of how colors mix; it and its three Color Laws are still taught. Grassman's work on this subject was inconsistent with that of Helmholtz . Grassmann also wrote on Crystallography , Electromagnetism , and Mechanics . Grassmann (1861) set out the first axiomatic presentation of arithmetic, making free use of the principle of induction. Peano and his followers cited this work freely starting around 1890. Curiously, Grassmann (1861) has never been translated into English. In 1862, Grassman published a thoroughly rewritten second edition of A1, hoping to earn belated recognition for his theory of extension, and containing the definitive exposition of his Linear Algebra . The result, ''Die Ausdehnungslehre: Vollständig und in strenger Form bearbeitet'', hereinafter denoted '''A2''', fared no better than A1, even though '''A2''''s manner of exposition anticipates the textbooks of the 20th century. The only mathematician to appreciate Grassmann's ideas during his lifetime was and Elie Cartan . A. N. Whitehead 's first monograph, the ''Universal Algebra'' (1898), included the first systematic exposition in English of the theory of extension and the Exterior Algebra . The theory of extension has been applied in the study of Differential Form s and in the application of such forms to Analysis and Geometry . Differential Geometry makes use of the Exterior Algebra . For an introduction to the role of Grassmann's work in contemporary Mathematical Physics , see Penrose (2004: chpts. 11, 12). LINGUIST Disappointed at his inability to be recognized as a mathematician, Grassmann turned to historical Linguistics . He wrote books on German grammar, collected folk songs, and learned Sanskrit . His dictionary and his translation of the Ayurveda (still in print) were recognized among philologists. He devised a sound law of Indo-European Languages , named Grassmann's Law in his honor. These philological accomplishments were honored during his lifetime; he was elected to the American Oriental Society and in 1876, he received a honorary doctorate from the University Of Tübingen . SEE ALSO REFERENCES Primary:
Secondary:
Extensive online bibliography, revealing substantial contemporary interest in Grassmann's life and work. References each chapter in Schubring. EXTERNAL LINKS
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