astronomy

Gheorghe Vrănceanu

Gheorghe Vrănceanu is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Gheorghe Vrănceanu rather than just read about it. In short: Gheorghe Vrănceanu (June 30, 1900 – April 27, 1979) was a Romanian mathematician, best known for his work in differential geometry and topology. He was titular member of the Romanian Academy and vice-president of the International Mathematical Union.

Key takeaways

Gheorghe Vrănceanu belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Gheorghe Vrănceanu to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Gheorghe Vrănceanu from memory before moving on to harder problems.

Reference excerpt

Gheorghe Vrănceanu (June 30, 1900 – April 27, 1979) was a Romanian mathematician, best known for his work in differential geometry and topology. He was titular member of the Romanian Academy and vice-president of the International Mathematical Union.

Biography He was born in 1900 in Valea Hogei, then a village in Vaslui County, now a component of Lipova commune, in Bacău County. He was the eldest of five children in his family. After attending primary school in his village and high school in Vaslui, he went to study mathematics at the University of Iași in 1919. There, he took courses with Alexandru Myller, Vera Myller, Simion Sanielevici, Victor Vâlcovici, and Simion Stoilow. After graduating in 1922, he went in 1923 to the University of Göttingen, where he studied under David Hilbert. Thereafter, he went to the University of Rome, where he studied under Tullio Levi-Civita, obtaining his doctorate on November 5, 1924, with thesis Sopra una teorema di Weierstrass e le sue applicazioni alla stabilità. The thesis defense committee was composed of 11 faculty, and was headed by Vito Volterra. Vrănceanu returned to Iași, where he was appointed a lecturer at the university. In 1927–1928, he was awarded a Rockefeller Foundation scholarship to study in France and the United States, where he was in a contact with Élie Cartan and Oswald Veblen. In 1929, he returned to Romania, and was appointed professor at the University of Cernăuți. In 1939, he moved to the University of Bucharest, where he was appointed Head of the Geometry and Topology department in 1948, a position he held until his retirement in 1970. His doctoral students include Henri Moscovici and Kostake Teleman. Vrănceanu was elected to the Romanian Academy as a corresponding member in 1946, then as a full member in 1955. From 1964 he was president of the Mathematics Section of the Romanian Academy. Also from 1964, he was an editor of the journal Revue Roumaine de mathématiques pures et appliquées, founded that year. At the International Congress of Mathematicians held in Vancouver, Canada in 1974, he was elected vice-president of the International Mathematical Union, a position he held from 1975 to 1978. He died in Bucharest in 1979 of an intestinal obstruction and was buried at the city's Bellu Cemetery. A high school in Bacău (Colegiul Național "Gheorghe Vrânceanu") is named after him, and so is a school in Lipova.

Research During his career, Vrănceanu published over 300 articles in journals throughout the world. His work covers a whole range of modern geometry, from the classical theory of surfaces, to the notion of non-holonomic spaces, which he discovered. In 1928 he gave an invited talk at the International Congress of Mathematicians in Bologna, titled Parallelisme et courbure dans une variété non holonome. In it, he introduced the notion of "non-holonomic manifolds," which are smooth manifolds provided with a smooth distribution that is generally not integrable.

Publications Vrănceanu, Gheorghe (1936). Les espaces non holonomes (PDF). Mémorial des sciences mathématiques (in French). Vol. 76. Paris: Gauthier-Villars. OCLC 1149255. Zbl 0013.28105. Vrănceanu, Gheorghe (1957). Leçons de géométrie différentielle, 2 Vols (in French). Bucharest: Éditions de l' Académie de la République Populaire Roumaine. MR 0124823. OCLC 488528715. Vrănceanu, Gheorghe (1959). "Tenseurs harmoniques et groupes de mouvement d'un espace de Riemann". Commentarii Mathematici Helvetici (in French). 33 (1): 161–173. doi:10.1007/BF02565914. MR 0107274. S2CID 120038943. Vrănceanu, Gheorghe; Ganea, Tudor (1961). "Topological embeddings of lens spaces". Proceedings of the Cambridge Philosophical Society. 57 (3): 688–690. Bibcode:1961PCPS...57..688V. doi:10.1017/S0305004100035751. MR 0124908. S2CID 122012809.

Notes

References Nicolescu, Liviu; Pripoae, Gabriel Teodor (2005). "Gheorghe Vrănceanu—successor of Gheorghe Tzitzeica at the geometry chair of the University of Bucharest" (PDF). Balkan Journal of Geometry and Its Applications. 10 (1): 11–20. MR 2209908.

Illustrations

Worked examples

Example 1 — a first encounter with Gheorghe Vrănceanu

Start with the simplest possible case. Write down what Gheorghe Vrănceanu claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Gheorghe Vrănceanu before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Gheorghe Vrănceanu ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Gheorghe Vrănceanu

In research: Gheorghe Vrănceanu appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Gheorghe Vrănceanu in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Gheorghe Vrănceanu is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1900 births, 1979 deaths, 20th-century Romanian mathematicians, so understanding it makes those chapters shorter.
In everyday life: Look for Gheorghe Vrănceanu outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Gheorghe Vrănceanu in 20 minutes

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Frequently asked questions

What is Gheorghe Vrănceanu in simple terms?

Why does Gheorghe Vrănceanu matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Gheorghe Vrănceanu?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Gheorghe Vrănceanu.