A **Lyndon word** is a non-empty string that is strictly smaller than all of its nontrivial suffixes in the lexicographical order. More formally, a string \( w \) is called a Lyndon word if it cannot be written as a nontrivial concatenation of two smaller strings, i.e.

A semiperfect magic cube is a three-dimensional generalization of a magic square. Just like a magic square, a semiperfect magic cube is an arrangement of numbers in a cube where the sums of the numbers in each row, each column, and the two main diagonals are all equal.

A train track map, also known as a railway map, is a graphical representation of a railway network. It typically shows the layout of tracks, stations, and other key features of the railway system. These maps can vary in detail and scale, ranging from highly detailed local maps that highlight specific lines and stations to broader regional or national maps that provide an overview of the entire railway network.

An edge-matching puzzle is a type of spatial reasoning puzzle in which the goal is to assemble a set of pieces with edges that match according to specific criteria. Each piece typically has different colors, patterns, or symbols along its edges, and the player must arrange the pieces so that adjacent edges share matching features.

A ranked poset (partially ordered set) is a specific type of poset that has an additional structure related to its elements' ranks. In a ranked poset, each element can be assigned a rank, which is a non-negative integer that gives a measure of the "level" or "height" of that element within the poset.

The Steiner Traveling Salesman Problem (STSP) is a variant of the classic Traveling Salesman Problem (TSP), which is a well-known problem in combinatorial optimization. In the traditional TSP, the goal is to find the shortest possible route that visits a set of given cities and returns to the original city. The challenge is to minimize the total distance traveled. The Steiner Traveling Salesman Problem extends this concept by allowing the introduction of additional points, known as Steiner points, into the route.

The Bass–Quillen conjecture is a conjecture in the field of algebraic K-theory, specifically concerning finitely generated infinite projective modules over a commutative ring. It was formulated by mathematicians Hyman Bass and Daniel Quillen in the 1970s.

Primary decomposition is a concept in the field of algebra, particularly in commutative algebra and algebraic geometry, that deals with the structure of ideals in a ring, specifically Noetherian rings. The primary decomposition theorem provides a way to break down an ideal into a union of 'primary' ideals.

"Coimage" can refer to different concepts depending on the context in which it's used, particularly in mathematics or computer science. Here are a couple of interpretations: 1. **In Mathematics (Category Theory):** The term "coimage" is often used in the context of category theory and algebraic topology. In this setting, the coimage of a morphism is related to the concept of the cokernel.

The Koszul–Tate resolution is a construction in algebraic geometry and homological algebra used to study certain algebraic structures, particularly those that involve differential forms or algebraic relations. It is named after Jean-Pierre Serre and William Tate, who contributed to the understanding of such resolutions. In simple terms, the Koszul-Tate resolution provides a way to resolve algebraic objects, such as modules or complexes associated with algebraic varieties, using tools from homological algebra.

The nilradical of a ring is an important concept in ring theory, a branch of abstract algebra. Specifically, the nilradical of a ring \( R \) is defined as the set of all nilpotent elements in \( R \). An element \( x \) of \( R \) is called nilpotent if there exists some positive integer \( n \) such that \( x^n = 0 \).

The term "local parameter" can have different meanings depending on the context in which it is used. Here are a few possible interpretations: 1. **In Mathematics**: A local parameter often refers to a variable that is used within a limited scope or specific region of a mathematical function or model. For example, in topology, local parameters can describe local properties of spaces or functions.

The domatic number of a graph is a concept in graph theory that describes the maximum number of disjoint dominating sets that can be formed within that graph. A dominating set is a subset of the vertices of a graph such that every vertex not in the set is adjacent to at least one vertex in the set.

In mathematics, a Novikov ring is a specific type of algebraic structure that arises in the context of algebraic topology and homological algebra, particularly in the study of loop homology and more generally in the theory of algebraic spaces that involve formal power series.

The 20th century saw significant contributions from Polish physicists in various fields, from theoretical physics to experimental work. Here are some notable figures and their contributions: 1. **Maria Skłodowska Curie (1867-1934)** - Although much of her work was completed in the early 20th century, she is renowned for her pioneering research on radioactivity, a term she coined.

The term "Test Ideal" generally refers to a concept in functional programming and software testing that emphasizes the importance of testing code under ideal conditions. It is often associated with the principles of clean code, maintainability, and test-driven development (TDD).

The term "system of parameters" can have different meanings depending on the context in which it's used. Here are a few possible interpretations across different fields: 1. **Mathematics and Statistics**: In the context of mathematical modeling or statistical analysis, a system of parameters refers to a set of variables that define a particular system or model. These parameters can influence the behavior of the system, and analyzing them can provide insights into the system's dynamics.

An optimization problem is a mathematical problem that seeks to find the best solution from a set of feasible solutions. The objective is to maximize or minimize a certain function, called the objective function, while satisfying a set of constraints that define the feasible region.

The longest uncrossed knight's path refers to a path traced by a knight on a chessboard where the knight visits each square without revisiting any square (i.e., without crossing over itself or visiting the same square more than once). This kind of problem is often explored in the context of graph theory and combinatorial optimization.