finite fold sequence
11Grushko theorem — In the mathematical subject of group theory, the Grushko theorem or the Grushko Neumann theorem is a theorem stating that the rank (that is, the smallest cardinality of a generating set) of a free product of two groups is equal to the sum of the… …
12DNA nanotechnology — seeks to make artificial, designed nanostructures out of nucleic acids, such as this DNA tetrahedron.[1] Each edge of the tetrahedron is a 20 base pair DNA double helix, and each vertex is a three arm junction. DNA n …
13Matrix (mathematics) — Specific elements of a matrix are often denoted by a variable with two subscripts. For instance, a2,1 represents the element at the second row and first column of a matrix A. In mathematics, a matrix (plural matrices, or less commonly matrixes)… …
14Christianity — /kris chee an i tee/, n., pl. Christianities. 1. the Christian religion, including the Catholic, Protestant, and Eastern Orthodox churches. 2. Christian beliefs or practices; Christian quality or character: Christianity mixed with pagan elements; …
15Penrose tiling — A Penrose tiling is a nonperiodic tiling generated by an aperiodic set of prototiles named after Roger Penrose, who investigated these sets in the 1970s.Because all tilings obtained with the Penrose tiles are non periodic, Penrose tilings are… …
16Combinatorial species — In combinatorial mathematics, the theory of combinatorial species is an abstract, systematic method for analysing discrete structures in terms of generating functions. Examples of discrete structures are (finite) graphs, permutations, trees, and… …
17Euclidean plane isometry — In geometry, a Euclidean plane isometry is an isometry of the Euclidean plane, or more informally, a way of transforming the plane that preserves geometrical properties such as length. There are four types: translations, rotations, reflections,… …
18Unitary group — In mathematics, the unitary group of degree n , denoted U( n ), is the group of n times; n unitary matrices, with the group operation that of matrix multiplication. The unitary group is a subgroup of the general linear group GL( n , C).In the… …
19Pi — This article is about the number. For the Greek letter, see Pi (letter). For other uses, see Pi (disambiguation). The circumference of a ci …
20Down syndrome — Classification and external resources Boy with Down syndrome assembling a …
