Line at infinity
The concept of the "line at infinity" arises primarily in projective geometry, a branch of mathematics that extends the properties of Euclidean geometry. In projective geometry, we can consider points and lines at infinity, which help to simplify and unify various geometric theorems and properties. ### Definition of Line at Infinity: 1. **Homogeneous Coordinates**: In projective geometry, points in the plane are represented using homogeneous coordinates.
Möbius transformation
A Möbius transformation (or linear fractional transformation) is a function defined on the complex numbers that has the general form: \[ f(z) = \frac{az + b}{cz + d} \] where \(a\), \(b\), \(c\), and \(d\) are complex numbers, and \(ad - bc \neq 0\) to ensure that the transformation is well-defined (i.e., it is not degenerate).
Oriented projective geometry
Oriented projective geometry is a branch of projective geometry that considers the additional structure of orientation. In traditional projective geometry, the focus is primarily on the properties of geometric objects that remain invariant under projective transformations, such as lines, points, and their relations. However, projective geometry itself does not inherently distinguish between different orientations of these objects. In oriented projective geometry, an explicit orientation is assigned to points and lines.
PSL(2,7)
PSL(2, 7) refers to the projective special linear group of 2x2 matrices over the finite field of order 7. More specifically, PSL(2, 7) is defined as the quotient of the special linear group SL(2, 7) by its center.
Pencil (geometry)
In geometry, a "pencil" typically refers to a collection of geometric objects that share a common property, often associated with points or lines. The most common usage involves a "pencil of lines" or "pencil of rays." ### Pencil of Lines: A pencil of lines is a set of lines that all pass through a single point, known as the "vertex" or "center" of the pencil.
Point-pair separation
Point-pair separation is a concept often used in various fields such as mathematics, computer science, and physics to describe the distance between a pair of points in a given space. It specifically focuses on measuring the minimum distance separating two distinct points, which can be important in applications such as spatial analysis, clustering, and geometric computations.
Polar hypersurface
In mathematics, particularly in algebraic geometry and complex geometry, the term "polar hypersurface" refers usually to a certain type of geometric object associated with a variety (a generalization of a surface or higher-dimensional analog) in a projective space.
Projective frame
A projective frame is a concept used in the field of projective geometry and related areas, typically dealing with the representation of points, lines, and geometric configurations in a projective space. The term "frame" can have different meanings depending on the specific context, but it generally refers to a coordinate system or a set of basis elements that allow for the description and manipulation of geometric entities within that space.
Projective harmonic conjugate
In the context of projective geometry, specifically within the study of projective transformations and properties of figures, the concept of a harmonic conjugate is related to the idea of harmonic sets of points.
Projective line
The projective line is a fundamental concept in projective geometry, representing a way to extend the notion of lines to include "points at infinity".
Provability logic
Provability logic is a branch of mathematical logic that studies formal systems of provability. Specifically, it deals with the properties and behaviors of provability predicates, which are statements or operators that express the idea that a certain statement is provable within a given formal system. One of the most prominent systems within provability logic is known as Gödel's provability logic, often represented by the modal system \( GL \) (Gödel-Löb logic).
Toronto space
"Toronto Space" can refer to a couple of different concepts depending on the context. Here are a few possibilities: 1. **Physical Spaces**: In a geographical or urban planning context, "Toronto space" may refer to various physical spaces in the city of Toronto, such as parks, public squares, community centers, and other public or private venues that serve as gathering places for residents and visitors.
Jean McSorley
Jean McSorley is not a widely recognized figure in popular culture or public life, and there might be multiple people with that name.
Ruth Coleman
Ruth Coleman could refer to multiple people, but one notable figure is Ruth Coleman, an American educator and administrator particularly known for her contributions to public education and her leadership roles in various educational institutions. She has a history of involvement in initiatives to improve educational policies and practices.
Maja Pohar
Maja Pohar is not a widely recognized term or name in general knowledge as of October 2023. It could refer to a person, a brand, a fictional character, or something specific in a local context. Without additional context, it’s difficult to provide a specific answer.
Stereographic projection
Stereographic projection is a method of projecting points from a sphere onto a plane. It works by projecting points from the surface of a sphere onto a plane that is tangent to the sphere at a specific point. This type of projection is commonly used in various fields, including cartography, complex analysis, and computer graphics.
The Geometry of an Art
"The Geometry of an Art" can refer to the intersection of mathematical concepts, particularly geometry, with artistic expression. This theme explores how geometric principles shape various art forms, encompassing topics like symmetry, proportion, perspective, and spatial relationships. Here are a few key areas where geometry plays a significant role in art: 1. **M.C. Escher**: The work of Dutch artist M.C.
Tropical projective space
Tropical projective space is a concept arising in tropical geometry, which is a piece of mathematics that studies geometric structures and mathematical objects using a combinatorial and polyhedral approach. Tropical geometry replaces classical algebraic geometry with a framework where arithmetic operations are modified in a specific way, leading to a simpler geometrical interpretation akin to a combinatorial structure.
Von Staudt conic
The Von Staudt conic is a specific type of conic section that arises in projective geometry, particularly in relation to a projective plane over a finite field. It can be defined as a conic section in the projective plane defined over a projective space that has certain geometrical properties. One of the key aspects of the Von Staudt conic is its connection to the study of various configurations of points and lines within projective geometry.
Decidability (logic)
In logic and computer science, **decidability** refers to the ability to determine, algorithmically, whether a given statement or problem can be definitively resolved as true or false within a specific formal system. A problem is said to be **decidable** if there exists an algorithm (or computational procedure) that will always produce a correct yes or no answer after a finite number of steps.