Belgian mathematician (1866 - 1962)
Charles-Jean Etienne Gustave Nicolas, baron de la Vallee Poussin
(
French pronunciation:
[?a?l
???
etj?n
?ystav
nik?la
ba???
d?
la
vale
pus??]
; 14 August 1866 ? 2 March 1962) was a
Belgian
mathematician
. He is best known for proving the
prime number theorem
.
The King of Belgium ennobled him with the title of
baron
.
Biography
[
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]
De la Vallee Poussin was born in
Leuven
,
Belgium
. He studied
mathematics
at the
Catholic University of Leuven
under his uncle Louis-Philippe Gilbert, after he had earned his
bachelor's degree
in
engineering
. De la Vallee Poussin was encouraged to study for a doctorate in
physics
and mathematics, and in 1891, at the age of just 25, he became an
assistant professor
in mathematical analysis.
De la Vallee Poussin became a professor at the same university (as was his father,
Charles Louis de la Vallee Poussin
, who taught
mineralogy
and
geology
) in 1892. De la Vallee Poussin was awarded with Gilbert's chair when Gilbert died. While he was a professor there, de la Vallee Poussin carried out research in mathematical analysis and the theory of numbers, and in 1905 was awarded the Decennial Prize for Pure Mathematics 1894?1903. He was awarded this prize a second time in 1924 for his work during 1914?23.
In 1898, de la Vallee Poussin was appointed as the correspondent to the
Royal Belgian Academy of Sciences
, and he became a Member of the Academy in 1908. In 1923, he became the President of the Division of Sciences.
In August 1914, de la Vallee Poussin escaped from Leuven at the time of its destruction by the invading
German Army
of
World War I
, and he was invited to teach at
Harvard University
in the
United States
. He accepted this invitation. In 1918, de la Vallee Poussin returned to Europe to accept professorships in
Paris
at the
College de France
and at
the Sorbonne
.
After the war was over, de la Vallee Poussin returned to Belgium, The International Union of Mathematicians was created, and he was invited to become its President. Between 1918 and 1925, de la Vallee Poussin traveled extensively, lecturing in
Geneva
,
Strasbourg
, and
Madrid
. and then in the United States where he gave lectures at the Universities of Chicago, California, Pennsylvania, and Brown University, Yale University, Princeton University, Columbia University, and the Rice Institute of Houston.
He was awarded the
Prix Poncelet
for 1916.
[1]
De la Vallee Poussin was given the titles of Doctor Honoris Causa of the Universities of Paris, Toronto, Strasbourg, and Oslo, an Associate of the Institute of France, and a Member of the
Pontifical Academy of Sciences
,
[2]
Nazionale dei Lincei, Madrid, Naples, Boston. He was awarded the title of Baron by
King Albert I of the Belgians
in 1928.
In 1961, de la Vallee Poussin fractured his shoulder, and this accident and its complications led to his death in
Watermael-Boitsfort
, near
Brussels, Belgium
, a few months later.
[3]
A student of his,
Georges Lemaitre
, was the first to propose the
Big Bang theory
of the formation of the
Universe
.
Work
[
edit
]
Although his first mathematical interests were in analysis, he became suddenly famous as he proved the
prime number theorem
independently of his coeval
Jacques Hadamard
in 1896.
Afterwards, he found interest in
approximation theory
. He defined, for any
continuous function
f
on the standard
interval
, the sums
- ,
where
and
are the vectors of the
dual basis
with respect to the
basis
of
Chebyshev polynomials
(defined as
Note that the formula is also valid with
being the
Fourier
sum of a
-
periodic function
such that
Finally, the de la Vallee Poussin sums can be evaluated in terms of the so-called
Fejer
sums (say
)
The kernel is bounded (
) and obeys the property
- , if
Later, he worked on
potential theory
and
complex analysis
.
He also published a counterexample to
Alfred Kempe
's false proof of the
four color theorem
. The
Poussin graph
, the graph he used for this counterexample, is named after him.
Cours d’analyse
[
edit
]
The textbooks of his mathematical analysis course have been a reference for a long time and had some international influence.
[4]
The second edition (1909-1912) is remarkable for its introduction of the Lebesgue integral. It was in 1912, "the only textbook on analysis containing both Lebesgue integral and its application to Fourier series, and a general theory of approximation of functions by polynomials".
[4]
The third edition (1914) introduced the now classical definition of
differentiability
due to
Otto Stolz
. The second volume of this third edition was burnt in the
fire of Louvain
during the
German invasion
.
The further editions were much more conservative, returning essentially to the first edition. Starting from the eighth edition, Fernand Simonart took over the revision and the publication of the
Cours d’analyse.
Selected publications
[
edit
]
- Œuvres
, vol. 1 (Biography and number theory), 2000 (eds. Mawhin, Butzer, Vetro), vols. 2 to 4 planned
- Cours d´Analyse
, 2 vols., 1903, 1906 (7th edition 1938), Reprint of the 2nd edition 1912, 1914 by Jacques Gabay,
ISBN
2-87647-227-9
(deals only with real analysis).
[5]
Online:
- Integrals de Lebesgue, fonctions d´ensemble, classes de Baire
,
[7]
2nd edition 1934, Reprint by Jacques Gabay,
ISBN
2-87647-159-0
- Le potentiel logarithmique, balayage et representation conforme
, Paris, Lowen 1949
- Recherches analytiques de la theorie des nombres premiers
, Annales de la Societe Scientifique de Bruxelles vol. 20 B, 1896, pp. 183?256, 281?362, 363?397, vol. 21 B, pp. 351?368 (prime number theorem)
- Sur la fonction Zeta de Riemann et le nombre des nombres premiers inferieur a une limite donnee
, Memoires couronnes de l Academie de Belgique, vol.59, 1899, pp. 1?74
- Lecons sur l'approximation des fonctions d'une variable reelle
Paris, Gauthier-Villars, 1919,
[8]
1952
See also
[
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]
Notes
[
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]
- ^
"Prix Poncelet"
.
Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences
: 791. 18 December 1916.
- ^
"Charles de la Vallee Poussin"
.
- ^
Burkill, J. C. (1964).
"Charles-Joseph de la Vallee Poussin"
.
Journal of the London Mathematical Society
: 165?175.
doi
:
10.1112/jlms/s1-39.1.165
.
- ^
a
b
Mawhin, Jean
(19 September 2014). "The Cours d'Analyse Infinitesimale of Charles-Jean de La Vallee Poussin: From Innovation to Tradition".
Jahresbericht der Deutschen Mathematiker-Vereinigung
.
116
(4): 243?259.
doi
:
10.1365/s13291-014-0100-z
.
ISSN
0012-0456
.
S2CID
119983767
.
- ^
Porter, M. B. (1915).
"Review:
Cours d'Analyse Infinitesmale
, by Ch.-J. de la Vallee Poussin"
(PDF)
.
Bull. Amer. Math. Soc
.
22
(2): 77?85.
doi
:
10.1090/s0002-9904-1915-02725-4
.
- ^
Porter, M. B. (1925).
"Review:
Cours d'Analyse Infinitesimale, Tome I
, by Ch. J. de la Vallee Poussin"
(PDF)
.
Bull. Amer. Math. Soc
.
31
(1): 83.
doi
:
10.1090/s0002-9904-1925-04009-4
.
- ^
Carmichael, R. D.
(1918).
"Review:
Integrals de Lebesgue, Fonctions d'Ensemble, Classes de Baire
, by C. de la Vallee Poussin"
(PDF)
.
Bull. Amer. Math. Soc
.
24
(7): 348?355.
doi
:
10.1090/s0002-9904-1918-03091-7
.
- ^
Jackson, Dunham
(1922).
"Review:
Lecons sur l'approximation des fonctions d'une variable reelle
, by C. de la Vallee Poussin"
(PDF)
.
Bull. Amer. Math. Soc
.
28
(1): 59?61.
doi
:
10.1090/S0002-9904-1922-03513-6
.
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