Dimitrie D. Pompeiu (; – 8 October 1954) was a

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, and ...

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

, professor at the

University of Bucharest The University of Bucharest ( ro, Universitatea din București), commonly known after its abbreviation UB in Romania, is a public university founded in its current form on by a decree of Prince Alexandru Ioan Cuza to convert the former Princel ...

, titular member of the

Romanian Academy The Romanian Academy ( ro, Academia Română ) is a cultural forum founded in Bucharest, Romania, in 1866. It covers the scientific, artistic and literary domains. The academy has 181 active members who are elected for life. According to its byl ...

, and President of the Chamber of Deputies.

Biography

He was born in 1873 in Broscăuți,

Botoșani County Botoșani County () is a county ( județ) of Romania, in Western Moldavia (encompassing a few villages in neigbhouring Suceava County from Bukovina to the west as well), with the capital town ( ro, Oraș reședință de județ) at Botoșani. ...

, in a family of well-to-do peasants. After completing high school in nearby

Dorohoi Dorohoi () is a municipiu, city in Botoșani County, Romania, on the right bank of the river Jijia, which broadens into a lake on the north. History Dorohoi used to be a market for the timber and farm produce of the north Moldavian highlands; m ...

, he went to study at the Normal Teachers School in

Bucharest Bucharest ( , ; ro, București ) is the capital and largest city of Romania, as well as its cultural, industrial, and financial centre. It is located in the southeast of the country, on the banks of the Dâmbovița River, less than north of ...

, where he had Alexandru Odobescu as a teacher. After obtaining his diploma in 1893, he taught for five years at schools in Galați and

Ploiești Ploiești ( , , ), formerly spelled Ploești, is a city and county seat in Prahova County, Romania. Part of the historical region of Muntenia, it is located north of Bucharest. The area of Ploiești is around , and it borders the Blejoi commune ...

. In 1898 he went to

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...

, where he studied mathematics at the

University of Paris , image_name = Coat of arms of the University of Paris.svg , image_size = 150px , caption = Coat of Arms , latin_name = Universitas magistrorum et scholarium Parisiensis , motto = ''Hic et ubique terrarum'' (Latin) , mottoeng = Here and a ...

(the

Sorbonne Sorbonne may refer to: * Sorbonne (building), historic building in Paris, which housed the University of Paris and is now shared among multiple universities. *the University of Paris (c. 1150 – 1970) *one of its components or linked institution, ...

). He obtained his

Ph.D. A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin: or ') is the most common degree at the highest academic level awarded following a course of study. PhDs are awarded for programs across the whole breadth of academic fields. Because it is ...

degree in mathematics in 1905, with thesis ''On the continuity of complex variable functions'' written under the direction of Henri Poincaré. After returning to Romania, Pompeiu was named Professor of

Mechanics Mechanics (from Ancient Greek: μηχανική, ''mēkhanikḗ'', "of machines") is the area of mathematics and physics concerned with the relationships between force, matter, and motion among physical objects. Forces applied to object ...

at the

University of Iași The Alexandru Ioan Cuza University ( Romanian: ''Universitatea „Alexandru Ioan Cuza"''; acronym: UAIC) is a public university located in Iași, Romania. Founded by an 1860 decree of Prince Alexandru Ioan Cuza, under whom the former Academia M ...

. In 1912, he assumed a chair at the

. In the early 1930s he was elected to the Chamber of Deputies as a member of

Nicolae Iorga Nicolae Iorga (; sometimes Neculai Iorga, Nicolas Jorga, Nicolai Jorga or Nicola Jorga, born Nicu N. Iorga;Iova, p. xxvii. 17 January 1871 – 27 November 1940) was a Romanian historian, politician, literary critic, memoirist, Albanologist, poet ...

's Democratic Nationalist Party, and served as President of the Chamber of Deputies for a year. In 1934, Pompeiu was elected titular member of the Romanian Academy, while in 1943 he was elected to the

Romanian Academy of Sciences The Romanian Academy of Sciences was an institution established in Romania by a group of 26 scientists, dissatisfied with the imperfect organization of the Scientific Section of the Romanian Academy, which was left in the background, with only 12 ...

. In 1945, he became the founding director of the

Institute of Mathematics of the Romanian Academy The "Simion Stoilow" Institute of Mathematics of the Romanian Academy is a research institute in Bucharest, Romania. It is affiliated with the Romanian Academy, and it is named after Simion Stoilow, one of its founders. History On December 2 ...

. He died in Bucharest in 1954. A boulevard in the

Pipera Pipera village is a neighborhood in Voluntari, Ilfov County, at the northern edge of the city of Bucharest, Romania. Development Until 1995, Pipera was an ordinary village. After that, an "El Dorado" of land transactions began. Plots of land th ...

neighborhood of the city is named after him, and so is a school in his hometown of Broscăuți.

Research

Pompeiu's contributions were mainly in the field of

mathematical analysis Analysis is the branch of mathematics dealing with continuous functions, limit (mathematics), limits, and related theories, such as Derivative, differentiation, Integral, integration, measure (mathematics), measure, infinite sequences, series (m ...

complex functions Complex analysis, traditionally known as the theory of functions of a complex variable, is the branch of mathematical analysis that investigates functions of complex numbers. It is helpful in many branches of mathematics, including algebrai ...

theory, and rational mechanics. In an article published in 1929, he posed a challenging conjecture in

integral geometry In mathematics, integral geometry is the theory of measures on a geometrical space invariant under the symmetry group of that space. In more recent times, the meaning has been broadened to include a view of invariant (or equivariant) transformati ...

, now widely known as the Pompeiu problem. Among his contributions to

real analysis In mathematics, the branch of real analysis studies the behavior of real numbers, sequences and series of real numbers, and real functions. Some particular properties of real-valued sequences and functions that real analysis studies include conv ...

there is the construction, dated 1906, of non-constant, everywhere differentiable functions, with derivative vanishing on a dense set. Such derivatives are now called Pompeiu derivatives.

Selected works

*. *. *.

Biographical references

* *

References

*. ("''Areolar derivative and functions of bounded variation''" is an important reference paper in the theory of areolar derivatives.) *. {{DEFAULTSORT:Pompeiu, Dimitrie 1873 births 1954 deaths People from Botoșani County University of Paris alumni 20th-century Romanian mathematicians Complex analysts Mathematical analysts Alexandru Ioan Cuza University faculty University of Bucharest faculty Titular members of the Romanian Academy Members of the Romanian Academy of Sciences Democratic Nationalist Party (Romania) politicians Presidents of the Chamber of Deputies (Romania)

Biography

Research

Selected works

See also

Biographical references

References