Search results
Results from the WOW.Com Content Network
In crystallography, a centrosymmetric point group contains an inversion center as one of its symmetry elements. [1] In such a point group, for every point (x, y, z) in the unit cell there is an indistinguishable point (-x, -y, -z). Such point groups are also said to have inversion symmetry. [2] Point reflection is a similar term used in geometry.
The inverse problem for the commutation relation AK = KA of identifying all involutory K that commute with a fixed matrix A has also been studied. [ 1 ] Symmetric centrosymmetric matrices are sometimes called bisymmetric matrices .
The Bauhinia blakeana flower on the Hong Kong region flag has C 5 symmetry; the star on each petal has D 5 symmetry. The Yin and Yang symbol has C 2 symmetry of geometry with inverted colors In geometry , a point group is a mathematical group of symmetry operations ( isometries in a Euclidean space ) that have a fixed point in common.
In mathematics, a symmetry operation is a geometric transformation of an object that leaves the object looking the same after it has been carried out. For example, a 1 ⁄ 3 turn rotation of a regular triangle about its center, a reflection of a square across its diagonal, a translation of the Euclidean plane, or a point reflection of a sphere through its center are all symmetry operations.
A symmetry of the projective plane with a given conic relates every point or pole to a line called its polar. The concept of centre in projective geometry uses this relation. The following assertions are from G. B. Halsted. [3] The harmonic conjugate of a point at infinity with respect to the end points of a finite sect is the 'centre' of that ...
Symmetry occurs not only in geometry, but also in other branches of mathematics. Symmetry is a type of invariance: the property that a mathematical object remains unchanged under a set of operations or transformations. [1] Given a structured object X of any sort, a symmetry is a mapping of the object
Figure 1: The point O is an external homothetic center for the two triangles. The size of each figure is proportional to its distance from the homothetic center. In geometry, a homothetic center (also called a center of similarity or a center of similitude) is a point from which at least two geometrically similar figures can be seen as a dilation or contraction of one another.
The term reflection is loose, and considered by some an abuse of language, with inversion preferred; however, point reflection is widely used. Such maps are involutions, meaning that they have order 2 – they are their own inverse: applying them twice yields the identity map – which is also true of other maps called reflections.