exterior vertex
11Beijing city fortifications — The city wall of Beijing was a fortification built around 1435. It was 23.5 km long. The thickness at ground level was 20m and the top 12m. The wall was 15m high, and it had nine gates. This wall stood for nearly 530 years, but in 1965 it was… …
12Speyer Cathedral — Speyer Cathedral * UNESCO World Heritage Site …
13Car Make T&E — is considered one of the top car tuning and fabrication shops in Japan. It was established on October 10, 1996 by Mr. Takahiro Ueno and is located in the Tsuzuki ku ward of Yokohama city. The brand concept is very simple Technical and Elegant are …
14Hyperbola — This article is about a geometrical curve, a conic section. For the term used in rhetoric, see Hyperbole …
15Pseudotriangle — In Euclidean plane geometry, a pseudotriangle is the simply connected subset of the plane that lies between any three mutually tangent convex sets. A pseudotriangulation is a partition of a region of the plane into pseudotriangles, and a pointed… …
16Regular polygon — A regular polygon is a polygon which is equiangular (all angles are congruent) and equilateral (all sides have the same length). Regular polygons may be convex or star.General propertiesThese properties apply to both convex and star regular… …
17Duality (mathematics) — In mathematics, a duality, generally speaking, translates concepts, theorems or mathematical structures into other concepts, theorems or structures, in a one to one fashion, often (but not always) by means of an involution operation: if the dual… …
18List of algebraic structures — In universal algebra, a branch of pure mathematics, an algebraic structure is a variety or quasivariety. Abstract algebra is primarily the study of algebraic structures and their properties. Some axiomatic formal systems that are neither… …
19Outline of algebraic structures — In universal algebra, a branch of pure mathematics, an algebraic structure is a variety or quasivariety. Abstract algebra is primarily the study of algebraic structures and their properties. Some axiomatic formal systems that are neither… …
20Delaunay triangulation — A Delaunay triangulation in the plane with circumcircles shown In mathematics and computational geometry, a Delaunay triangulation for a set P of points in the plane is a triangulation DT(P) such that no point in P is inside the circumcircle of… …
