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Mac Lane's planarity criterion, also known as the "Mac Lane's formation", is a combinatorial condition used to determine whether a graph can be embedded in the plane without any edges crossing. Specifically, the criterion states that a graph is planar if and only if it does not contain a specific type of subgraph as a "minor.

The minimum rank of a graph is a concept from algebraic graph theory that is associated with the graph's adjacency matrix or Laplacian matrix. Specifically, it refers to the smallest rank among all real symmetric matrices corresponding to the graph.

Modularity, in the context of networks, refers to the degree to which a network can be divided into smaller, disconnected sub-networks or communities. It is often used in network analysis to identify and measure the strength of division of a network into modules, which are groups of nodes that are more densely connected to each other than to nodes in other groups. ### Key Points about Modularity: 1. **Community Structure**: Modularity helps in detecting community structure within networks.

A Ramanujan graph is a type of expander graph named after the Indian mathematician Srinivasa Ramanujan, whose work in number theory inspired this concept. Ramanujan graphs are particularly characterized by their exceptional expansion properties and have applications in various areas of mathematics and computer science, including combinatorics, number theory, and network theory.

Raissa D'Souza is a prominent figure in the field of computer science, known for her contributions to areas such as data science, machine learning, and scientific computing. She is affiliated with the University of California, Davis, where she focuses on research that combines computer science and applied mathematics. D'Souza has published numerous papers and has been involved in various educational initiatives and programs aimed at advancing knowledge in computing and data analysis.

A semi-symmetric graph is a type of graph that exhibits certain symmetrical properties but does not necessarily exhibit full symmetry. More formally, a semi-symmetric graph can be defined through its vertex and edge structure in relation to their automorphisms and symmetrical actions. In the context of graph theory, the properties that characterize a semi-symmetric graph can vary somewhat depending on the specific definition being used. Generally, however, a semi-symmetric graph maintains some degree of regularity and uniformity in its structure.

Spectral clustering is a technique used in machine learning and data analysis for grouping data points into clusters based on the properties of the dataset. It leverages the eigenvalues and eigenvectors of matrices derived from the data, particularly the similarity matrix, to identify clusters. Here’s an overview of the key steps and concepts involved in spectral clustering: 1. **Similarity Graph**: First, a similarity graph is constructed from the data points.

Spectral graph theory is a branch of mathematics that studies the properties of graphs through the eigenvalues and eigenvectors of matrices associated with them. These matrices include the adjacency matrix, the degree matrix, and the Laplacian matrix, among others. Spectral graph theory connects combinatorial properties of graphs with linear algebra and provides powerful tools for analyzing graphs in various contexts.

A symmetric graph is a type of graph that exhibits a certain level of symmetry in its structure. More formally, a graph \( G \) is considered symmetric if, for any two vertices \( u \) and \( v \) in \( G \), there is an automorphism of the graph that maps \( u \) to \( v \).

A "two-graph" typically refers to a specific type of graph in the field of graph theory, but it might not be a widely standardized term. In general, graph theory involves studying structures made up of vertices (or nodes) connected by edges.

As of my last knowledge update in October 2023, there isn't a widely recognized figure, concept, or entity named "Ralph Bown." It's possible that it could refer to a lesser-known individual, a fictional character, or a recent event or development that emerged after that date.

The Leibniz operator is a differential operator used in the context of calculus, particularly in the formulation of differentiating products of functions. It is named after the mathematician Gottfried Wilhelm Leibniz, who made significant contributions to the development of calculus.

Polyadic algebra is a branch of algebra that extends the concept of traditional algebraic structures, such as groups, rings, and fields, to include operations that involve multiple inputs or arities. In particular, it focuses on operations that can take more than two variables (unlike binary operations, which are the most commonly studied).

Predicate functor logic is a formal system that combines elements of predicate logic with concepts from category theory, specifically functors. To understand it, it's helpful to break down the two main components: 1. **Predicate Logic**: This is an extension of propositional logic that includes quantifiers and predicates. In predicate logic, statements can involve variables and can assert relationships between objects.

Cohomology theories are mathematical frameworks used in algebraic topology, geometry, and related fields to study topological spaces and their properties. They serve as tools for assigning algebraic invariants to topological spaces, allowing for deeper insights into their structure. Cohomology theories capture essential features such as connectivity, holes, and other topological characteristics. ### Key Concepts in Cohomology Theories 1.

Double torus knots and links are concepts from the field of knot theory, which is a branch of topology. In topology, knots are considered as embeddings of circles in three-dimensional space, and links are collections of such embeddings. ### Double Torus A double torus is a surface that is topologically equivalent to two tori (the plural of torus) connected together. It's often visualized as the shape of a "figure eight" or a surface with two "holes.

Ralph Hartley (1888–1970) was an American engineer and mathematician known for his contributions to information theory and telecommunications. He is particularly recognized for developing the Hartley function, which quantifies the amount of information or the capacity of a signal. In 1928, he introduced the concept of "Hartley's Law," which states that the amount of information is proportional to the logarithm of the number of possible outcomes.

K-theory is a branch of mathematics that studies vector bundles and more generally, topological spaces and their associated algebraic invariants. It has applications in various fields, including algebraic geometry, operator theory, and mathematical physics. The core idea in K-theory involves the classification of vector bundles over a topological space. Specifically, there are two main types of K-theory: 1. **Topological K-theory**: This version studies topological spaces and their vector bundles.

Knot theory is a branch of mathematics that studies mathematical knots, which are loops in three-dimensional space that do not intersect themselves. It is a part of the field of topology, specifically dealing with the properties of these loops that remain unchanged through continuous deformations, such as stretching, twisting, and bending, but not cutting or gluing. In knot theory, a "knot" is defined as an embedded circle in three-dimensional Euclidean space \( \mathbb{R}^3 \).

Topological graph theory is a branch of mathematics that studies the interplay between graph theory and topology. It focuses primarily on the properties of graphs that are invariant under continuous transformations, such as stretching or bending, but not tearing or gluing. The key aspects of topological graph theory include: 1. **Graph Embeddings**: Understanding how a graph can be drawn in various surfaces (like a plane, sphere, or torus) without edges crossing.