Metric geometry stubs
Metric geometry is a branch of mathematics that studies geometric properties and structures based on the notion of distance. It focuses on spaces where distances between points are defined, and it often involves concepts such as metric spaces, geodesics, and notions of convergence and continuity. The term "metric geometry stubs" typically refers to short or incomplete articles (stubs) in a wiki or online encyclopedia about specific topics within metric geometry.
Aleksandrov–Rassias problem
The Aleksandrov–Rassias problem is a specific problem in the field of functional analysis and geometry, particularly concerning the behavior of certain mathematical functions under substitutions or perturbations. It focuses on determining when a function that satisfies a certain condition in a particular format can be approximated or is related to a function that meets a fundamental equation or inequality form, such as a triangle inequality.
Assouad–Nagata dimension
The Assouad–Nagata dimension is a notion from fractal geometry that helps characterize the "size" or "complexity" of a metric space in terms of its scaling behavior with respect to distances. It is a concept that generalizes the idea of dimension to accommodate the intricacies of more complex, fractal-like sets.
Banach fixed-point theorem
The Banach fixed-point theorem, also known as the contraction mapping theorem, is a fundamental result in fixed-point theory within the field of analysis.
Banach–Mazur compactum
The Banach–Mazur compactum is a specific topological space that arises in the context of functional analysis and topology, particularly in the study of the properties of Banach spaces. It is named after mathematicians Stefan Banach and Juliusz Mazur. The Banach–Mazur compactum can be defined as follows: - Consider the collection of all finite-dimensional normed spaces over the real numbers.
Carathéodory metric
The Carathéodory metric is a way to define a metric on certain types of manifolds, particularly in the context of complex analysis and several complex variables. It is named after the Greek mathematician Constantin Carathéodory, who developed concepts related to the theory of conformal mappings and complex geometry. In particular, the Carathéodory metric is used to study the geometry of domains in complex spaces.
Cartan–Hadamard theorem
The Cartan-Hadamard theorem is a result in differential geometry, particularly concerning the geometry of Riemannian manifolds. It establishes conditions under which a complete Riemannian manifold without boundary is diffeomorphic to either the Euclidean space or has certain geometric properties related to curvature. Specifically, the theorem states that: If \( M \) is a complete, simply connected Riemannian manifold with non-positive sectional curvature (i.e.
Cayley–Klein metric
The Cayley-Klein metric is a generalization of the metric of Euclidean space, adapted to describe curved spaces and geometries that arise in various mathematical and physical contexts. Named after mathematicians Arthur Cayley and Felix Klein, the Cayley-Klein framework allows for the derivation of metrics for different geometric contexts by altering the underlying algebraic structure. In its essence, the Cayley-Klein metric is constructed by starting from a basic geometric framework represented by a set of axioms or transformations.
Chow–Rashevskii theorem
The Chow–Rashevskii theorem is a fundamental result in differential geometry and the theory of control systems. It pertains to the accessibility of points in a control system defined by smooth vector fields.
Recursive filter
A recursive filter, often referred to as a recursive digital filter, is a type of digital filter that uses feedback in its processing. This means that the output of the filter at a given time depends not only on the current input but also on previous outputs. This feedback loop allows for specific characteristics in signal processing, such as memory and the ability to maintain a longer effect of the input data.
Reverberation mapping
Reverberation mapping is an astronomical technique used to study the inner workings of active galactic nuclei (AGNs), particularly supermassive black holes at the centers of galaxies. This method provides insight into the structure and dynamics of the gas and dust surrounding these black holes. The basic principle of reverberation mapping involves observing variations in the light emitted by an AGN over time.
Conformal dimension
The concept of **conformal dimension** is a mathematical notion that appears in the fields of geometric analysis and geometric topology, particularly in the context of fractals and metric spaces. The conformal dimension of a metric space is a measure of the "size" of the space with respect to conformal (angle-preserving) mappings. In simpler terms, it quantifies how the space can be "stretched" or "compressed" while maintaining angles.
Convex cap
A **convex cap** typically refers to a mathematical concept used in various fields, including optimization and probability theory. However, the term might also be context-specific, so I’ll describe its uses in different areas: 1. **Mathematics and Geometry**: In geometry, a convex cap can refer to the convex hull of a particular set of points, which is the smallest convex set that contains all those points.
Danzer set
A Danzer set is a concept from the field of discrete geometry, specifically relating to the arrangement of points in Euclidean space. It is named after the mathematician Ludwig Danzer, who studied these configurations. A Danzer set in the Euclidean space \( \mathbb{R}^n \) is defined as a set of points with the property that any bounded convex set in \( \mathbb{R}^n \) contains at least one point from the Danzer set.
Dimension function
The "dimension function" can refer to a few different concepts depending on the context in which it's used. Here are some common interpretations: 1. **Mathematics/Linear Algebra**: In the context of vector spaces, the dimension function refers to the function that assigns a natural number to a vector space, indicating the number of vectors in a basis for that space.
Distance (graph theory)
In graph theory, the **distance** between two vertices (or nodes) in a graph is defined as the length of the shortest path connecting them. The length of a path is typically measured by the number of edges it contains. Therefore, the distance \( d(u, v) \) between two vertices \( u \) and \( v \) is the minimum number of edges that need to be traversed to get from \( u \) to \( v \).
Distance set
A distance set is a mathematical concept often used in various fields, including geometry, topology, and combinatorics. It generally refers to a collection of points that are defined based on distances from a set of reference points according to a specific metric. One common context where distance sets are discussed is in the study of geometric configurations. For a given set of points in a metric space, a distance set may contain the pairwise distances between those points.
Doubling space
Doubling space is a concept often used in various fields, including mathematics, computer science, and physics, and it can refer to different ideas depending on the context. 1. **Mathematics and Geometry**: In the context of mathematical spaces, doubling often refers to the property of metric spaces where ball sizes can be controlled by the number of smaller balls that can cover the larger ones.
Equilateral dimension
Equilateral dimension typically refers to a concept in mathematics and geometry, often concerning the properties or characteristics of an object or shape that has equal dimensions in certain aspects. However, it's possible that you're referring to a specific application or definition within a niche area, such as in topology, fractal geometry, or even theoretical physics. In general mathematical contexts, it might relate to how dimensions are measured uniformly across a shape.
Equivalence of metrics
The equivalence of metrics is a concept in metric spaces that refers to the idea that two different metrics define the same topology on a set. In more formal terms, two metrics \( d_1 \) and \( d_2 \) on a set \( X \) are said to be equivalent if they induce the same notions of convergence, continuity, and open sets.