Robert Jentzsch

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Robert Georg Adolf Alfred Jentzsch (born November 4, 1890 in Königsberg , † March 21, 1918 in the Battle of Cambrai ) was a German mathematician and poet .

Live and act

Jentzsch was born in Königsberg in 1890 as the youngest of four children. His father, Alfred Jentzsch , was a professor of geology in Königsberg and later in Berlin. He was the brother of the physicist Felix Jentzsch .

The young Jentzsch graduated from the Prinz-Heinrich-Gymnasium in Berlin . With the university entrance qualification in his pocket, Jentzsch moved to Jena to study mathematics there. But he only stayed one semester in Jena and moved back to Berlin. In 1908 he enrolled at the then Friedrich Wilhelm University in Berlin as a mathematics student. Between 1911 and 1912 he studied in Munich for a year before returning to Berlin. There he received his doctorate in 1914 from Ferdinand Georg Frobenius on the subject of investigations into the theory of the consequences of analytical functions and received the award “summa cum laude”.

Frobenius was so impressed by him that he proposed him as a candidate for an extraordinary professorship before his habilitation, which Issai Schur then received. Jentzsch heard lectures from Professors Max Planck , Issai Schur, Hermann Amandus Schwarz , Friedrich Schottky and Edmund Landau .

Immediately after his doctorate, Jentzsch was drafted and relatively quickly promoted to lieutenant in the reserve. In December 1916 he completed his habilitation and became a private lecturer in Berlin, but due to military service in France he only got to give lectures in the summer semester of 1917. Even during his time at the front, he continued his mathematical work, as he was provided with literature by his friend Erika Schnell , who also studied mathematics.

In addition to his mathematician career, Robert Jentzsch also devoted himself to another occupation - poetry. He was a member of the expressionist Berlin poets' association Der Neue Club , in which the well-known poet and close friend of his, Georg Heym , also participated. Heym's tragic death while ice skating in January 1912 hit Jentzsch hard. He distanced himself from the "New Club", but also continued to write poetry in addition to his mathematical studies - under the influence of August Derleth and Stefan George . Some of his literary estate has been preserved through his correspondence with Erika Schnell and is in the archive of the Academy of Arts in Berlin and in the German Literature Archive in Marbach.

Robert Jentzsch was last battalion leader in the telecommunications company and fell on March 21, 1918 at the age of 27 by a chain bomb in the Battle of Cambrai on the St. Quentin Canal as part of the German spring offensive that was just beginning. He was a bearer of the Iron Cross 2nd and 1st class.

In his dissertation, Jentzsch dealt with power series . In particular, he proved that for power series with a positive radius of convergence R, every point on the edge of the convergence area (circle with radius R) is the accumulation point of the zeros of the partial sums of the power series. This generalizes the situation with the power series , in which every point on the circle with radius R = 1 in the complex number plane is the accumulation point of the zeros of the corresponding partial sums (the nth roots of units).

Fonts

  • Robert Jentzsch: Investigations on the theory of the consequences of analytical functions , Acta Mathematica, Vol. 41, 1917, pp. 219-251, pp. 253-270

literature

  • Peter Duren, Anne-Katrin Herbig, Dmitry Khavinson: Robert Jentzsch, mathematician and poet . The Mathematical Intelligencer (accepted for publication 2007, accessed online February 3, 2008), German translation Mitteilungen DMV 2008
  • Richard Sheppard The Writings of the New Club 1906 1914 , 2 vols., Gerstenberg Verlag, Hildesheim, 1980, 1983 (with prints of poems by Jentzsch)
  • Milton A. Cohen: Movement, Manifesto, Melee: The Modernist Group, 1910-1914 . Lanham: Lexington Books 2004 ISBN 0739109057
  • Reinhold Remmert: Classical Topics in Complex Function Theory , 1998, Springer, ISBN 0387982213
  • Paul Raabe , Ingrid Hannich-Bode: The authors and books of literary expressionism. Metzler, 1985, ISBN 3476005755 .
  • Tom Riebe (Ed.): Robert Jentzsch. Versensporn - Booklet for lyrical charms No. 29, Edition POESIE SCHMECKT GUT, Jena 2017, 100 copies.

Web links

Individual evidence

  1. ^ Proof z. B. in Titchmarsh Theory of Functions , 2nd Edition, p. 238
personal data
SURNAME Jentzsch, Robert
ALTERNATIVE NAMES Jentzsch, Robert Georg Adolf Alfred (full name)
BRIEF DESCRIPTION German mathematician
DATE OF BIRTH November 4, 1890
PLACE OF BIRTH Koenigsberg
DATE OF DEATH March 21, 1918
Place of death Battle of Cambrai