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Mellin, Yalmar

Yalmar Mellin (full name Robert Jalmar Mellin , fin. Robert Hjalmar Mellin , June 19, 1854, Liminka , Grand Duchy of Finland - April 5, 1933, Helsinki , Finland ) - Finnish mathematician, expert in the theory of functions, who developed one of the most famous integral transformations named after him is the Mellin transform .

Yalmar Mellin
Hjalmar mellin
Robert Hjalmar Mellin 0.jpeg
Robert Yalmar Mellin
Date of BirthJune 19, 1854 ( 1854-06-19 )
Place of BirthLiminka , Grand Duchy of Finland (now Finland )
Date of deathApril 5, 1933 ( 1933-04-05 ) (78 years)
Place of deathHelsinki , Finland
A country Grand Duchy of Finland → Finland
Scientific fieldmaths
Place of work
Alma materAlexandrovsky University (1840)
supervisorGösta Mittag-Leffler
Famous studentsErnst Lindelöf [1]

Biography

Yalmar Mellin was born on June 19, 1854 in Liminka , in Northern Ostrobothnia , just south of the city of Oulu , about 600 km north of Helsinki . His father was a priest. Yalmar Mellin grew up and received school education in the city of Hämeenlinna , about 100 km north of Helsinki , and then entered the Imperial Alexander University , where his teacher was the famous mathematician Gösta Mittag-Leffler [2] .

In the fall of 1881, he defended his thesis on the algebraic functions of one complex variable . After that, twice, in 1881 and 1882, he traveled to Berlin to work under the direction of Karl Weierstrass , and in 1883-1884 he came to Stockholm to continue working with Gösta Mittag-Leffler . From 1884 to 1891, he was an associate professor at Stockholm University , but did not give any lectures [2] .

Also in 1884, he was appointed senior lecturer at the newly established Helsinki Polytechnic Institute . In 1904-1907 he was the rector of this institute, and from 1907 he worked as a professor of mathematics, until his retirement in 1926 [2] .

Member of the Finnish Academy of Sciences (1908) [3] .

Scientific Results

A significant part of Yalmar Mellin's research is related to the development and use of the integral transform , which was given his name — the Mellin transform [4] . The core of the Mellin integral transform is a power functionxs-one {\ displaystyle x ^ {s-1}}   , and the Mellin transform on functionf(x) {\ displaystyle f (x)}   defined as

{Mf}(s)=φ(s)=∫0∞xs-onef(x)dx{\ displaystyle \ left \ {{\ mathcal {M}} f \ right \} (s) = \ varphi (s) = \ int _ {0} ^ {\ infty} x ^ {s-1} f (x ) {\ rm {d}} x}   .

The inverse Mellin transform is given by the formula

{M-oneφ}(x)=f(x)=one2πi∫c-i∞c+i∞x-sφ(s)ds{\ displaystyle \ left \ {{\ mathcal {M}} ^ {- 1} \ varphi \ right \} (x) = f (x) = {\ frac {1} {2 \ pi i}} \ int _ {ci \ infty} ^ {c + i \ infty} x ^ {- s} \ varphi (s) \, {\ rm {d}} s}   ,

where integration is carried out along a vertical straight line in the complex plane of the variable s , and the choice of a real parameter c must satisfy certain conditions specified in .

Notes

  1. ↑ Robert Hjalmar Mellin (Neopr.) (HTML). Mathematics Genealogy Project, Department of Mathematics, North Dakota State University. The appeal date is August 22, 2012. Archived October 29, 2012.
  2. ↑ 1 2 3 R. Paris. Robert Hjalmar Mellin (Neopr.) (HTML). School of Mathematics and University of St. Petersburg Andrews, Scotland. The appeal date is August 22, 2012. Archived October 29, 2012.
  3. ↑ Correspondence of S. V. Kovalevskaya and G. Mittag-Leffler. (Scientific Heritage, Volume 07). - M .: Science, 1984. - p. 299
  4. ↑ Eric W. Weisstein. Mellin Transform (Neopr.) (HTML). MathWorld - mathworld.wolfram.com. The appeal date is August 22, 2012.
Source - https://ru.wikipedia.org/w/index.php?title=Mellin,_Yalmar&oldid=94611491


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