In mathematics, graph theory is the study of graphs, which are mathematical structures used to model pairwise relations between objects. A graph in this context is made up of vertices (also called nodes or points) which are connected by edges (also called links or lines). A distinction is made between undirected graphs, where edges link two vertices symmetrically, and directed graphs, where edges link two vertices asymmetrically. Graphs are one of the principal objects of study in discrete mathematics.

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**Graph theory**

Article Snippet :faces of a convex polyhedron was studied and generalized by Cauchy and L'Huilier, and represents the beginning of the branch of mathematics known as topology

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**Leonhard Euler**

Article Snippet :study and generalization of this formula, specifically by Cauchy and L'Huilier, is at the origin of topology. Some of Euler's greatest successes were

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**Simon Antoine Jean L'Huilier**

Article Snippet :Simon Antoine Jean L'Huilier (or L'Huillier) (24 April 1750 in Geneva – 28 March 1840 in Geneva) was a Swiss mathematician of French Huguenot descent

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**Topological space**

Article Snippet :generalization of this formula, specifically by Cauchy (1789-1857) and L'Huilier (1750-1840), boosted the study of topology. In 1827, Carl Friedrich Gauss

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**Solid angle**

Article Snippet :that is purely a function of the vertex angles θa, θb, θc is given by L'Huilier's theorem as tan ( 1 4 Ω ) = tan ( θ s 2 ) tan ( θ s − θ a 2 ) tan

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**Spherical trigonometry**

Article Snippet :example, Todhunter, (Art.101—103) gives ten examples including that of L'Huilier: tan 1 4 E = tan 1 2 s tan 1 2 ( s − a ) tan 1 2 ( s − b ) tan

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**L'Huillier**

Article Snippet :and archbishop of the Orthodox Church in America Simon Antoine Jean L'Huilier (or L'Huillier) (1750–1840), Swiss mathematician Fort L'Huillier (sometimes

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**André Thevet**

Article Snippet :par l'auteur, & incogneues de noz anciens & modernes, Paris, Pierre l'Huilier. 1584 Vrais pourtraits et vies des hommes illustres MS: Grand Insulaire

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**Cours d'Analyse**

Article Snippet :notation “Lim.” for limit was first used by Simon Antoine Jean L'Huilier (1750–1840) in [L’Huilier 1787, p. 31]. Cauchy wrote this as “lim.” in [Cauchy 1821

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**French invasion of the Isle of Wight**

Article Snippet :Mémoires de Mess. Martin du Bellay Seigneur de Langay (A l'Olivier de P. l'Huilier, Paris 1569) pp. 340-41. (in French) (T.N.A. Discovery Catalogue): Account