Opaque set
In set theory and mathematics, an "opaque set" is not a standard or commonly used term. However, the concept of an opaque set might be used informally in certain contexts to refer to a set whose elements or the properties of which are not fully transparent or visible, or whose characteristics cannot be easily discerned. If you're encountering the term "opaque set" in a specific mathematical context, programming language, or another field, it may have a specialized meaning.
Orchard-planting problem
The orchard-planting problem is a problem in optimization typically found in operations research and mathematical programming. It involves the strategic placement of trees or plants in an orchard to maximize certain objectives while adhering to constraints. The problem can vary in its specifics, but it often includes considerations like: 1. **Maximizing Yield**: The primary goal is often to maximize the yield of fruits or nuts from the planted trees. This can depend on factors like tree density, spacing, and compatibility between different species.
Packing density
Packing density, often referred to in contexts such as materials science, chemistry, and physics, is a measure of how densely a certain volume is filled with particles, such as atoms, molecules, or other small entities. It is typically expressed as a ratio or a percentage, quantifying the proportion of space occupied by the particles in comparison to the total available space.
Penrose tiling
Penrose tiling is a non-periodic tiling generated by an aperiodic set of prototiles, named after the mathematician and physicist Roger Penrose, who studied these patterns in the 1970s. Unlike traditional tiling that can be periodically repeated, Penrose tilings cannot be exactly repeated in a regular pattern. They exhibit a form of symmetry that is both intricate and ordered, yet they do not repeat, which leads to fascinating mathematical and artistic properties.
Pinwheel tiling
Pinwheel tiling is a form of aperiodic tiling, which means it can cover a plane without repeating patterns while still being composed of simple geometric shapes. Specifically, pinwheel tiling uses a set of shapes known as "pinwheels" and is notable for its ability to create complex patterns that do not exhibit translational symmetry. The concept of pinwheel tiling was introduced by mathematician Robert Ammann in the 1970s.
Polycube
A polycube is a three-dimensional geometric shape formed by joining several cubes together along their faces. These shapes can take various forms and configurations, depending on how the cubes are arranged. Polycubes can be considered a three-dimensional analog of polyominoes, which are shapes formed by connecting squares in two dimensions. Polycubes are often studied in mathematics and computer science for their properties and applications, including in fields like combinatorial geometry, topology, and even in puzzle design.
Quaquaversal tiling
Quaquaversal tiling refers to a type of tiling pattern that exhibits a unique property of being the same regardless of the orientation from which it is viewed. The term "quaquaversal" is derived from a Latin term meaning "going in all directions," and in the context of tiling, it denotes a pattern that extends outward in multiple directions from a central point.
Regular map (graph theory)
In graph theory, a **regular map** is a specific type of graph that satisfies certain symmetrical properties related to vertex and face structure.
Roberts's triangle theorem
Roberts's Triangle Theorem is a result in geometry concerning the relationship between the areas of certain triangles formed by points on the sides of a given triangle.
Sphere packing
Sphere packing is the arrangement of spheres in a given space or volume in such a way that the spheres occupy the maximum possible volume without overlapping. It is a topic of interest in various fields such as mathematics, physics, and materials science. The most well-known packing configuration is the face-centered cubic (FCC) packing, which is one of the most efficient ways to pack spheres, achieving a maximum packing density of about 74%.
Sphere packing in a cylinder
Sphere packing in a cylinder refers to the arrangement of spheres (or solid balls) within a cylindrical space in a way that maximizes the number of spheres that can fit inside the cylinder. This is a specific case of a more general problem in the field of discrete geometry and optimization, where the goal is to understand how to efficiently pack objects in given volumes.
Squaring the square
"Squaring the square" refers to a mathematical problem in tiling, specifically involving the arrangement of squares within a square. The challenge is to subdivide a larger square into smaller squares, all of different sizes, such that there are no gaps or overlaps. The most famous solution to this problem was found by the mathematician Henry Dudeney in 1907. He created a square that was subdivided into 36 smaller squares, all of which were of distinct sizes.
Straight skeleton
A straight skeleton is a geometric construct that is generated from a polygon by tracing its edges and creating a new structure that reflects the shape of the original polygon. It is particularly significant in computational geometry and has applications in areas such as computer graphics, urban planning, and architecture. ### Definition To create a straight skeleton for a given polygon: 1. **Starting Point**: Begin with a simple polygon, which can be convex or concave but should not have holes.
Tarski's circle-squaring problem is a famous problem in the field of geometry and mathematics, proposed by the logician and mathematician Alfred Tarski in 1925. The problem involves the task of transforming a circle into a square (or vice versa) with the same area, using only a finite number of straightedge and compass constructions. Specifically, the question is whether it is possible to construct, with traditional geometric methods (i.e.
The Erdős Distance Problem
The Erdős Distance Problem is a classic problem in combinatorial geometry that concerns the maximum number of distinct distances that can be formed by a finite set of points in the plane. Specifically, the problem is named after the Hungarian mathematician Paul Erdős. The fundamental question can be stated as follows: Given a finite set of \( n \) points in the plane, what is the maximum number of distinct distances that can be formed between pairs of points in this set?
Voronoi diagram
A Voronoi diagram is a mathematical structure that partitions a space into regions based on the distance to a specific set of points, called seed points or sites. Each region in a Voronoi diagram corresponds to one of the seed points, and every point within that region is closer to its associated seed point than to any other seed point.
Weighted Voronoi diagram
A Weighted Voronoi Diagram is a variation of the standard Voronoi diagram that incorporates weights assigned to each point (or site) in the space. In a typical Voronoi diagram, the space is divided into regions based on the proximity to a set of points, where each point's region consists of all locations closer to that point than to any other.