A Mori domain is a concept in the field of algebraic geometry, particularly in the study of algebraic varieties and their properties. It is a type of algebraic structure that arises in the context of Mori theory, which is concerned with the classification of algebraic varieties and the birational geometry of these varieties. In more specific terms, a Mori domain is typically a normal, irreducible, and properly graded algebraic domain that satisfies certain conditions related to the Mori program.
The Mori–Nagata theorem is a result in algebraic geometry, particularly concerning the structure of algebraic varieties and their properties under certain conditions. Named after Shigeo Mori and Masayuki Nagata, the theorem deals with the existence of a specific type of morphism called a "rational map" between varieties.
In the context of mathematics, particularly in the fields of algebra and number theory, a **multiplicatively closed set** is a subset of a given set that is closed under the operation of multiplication. This means that if you take any two elements from this set and multiply them together, the result will also be an element of the set. Formally, let \( S \) be a set.
In algebraic geometry and commutative algebra, a **multiplier ideal** is a conceptual tool used to study the properties of singularities of algebraic varieties and to generalize notions of regularity and divisor theory. Multiplier ideals arise in the context of *Cohen-Macaulay* rings and provide a way to handle sheaf-theoretic aspects of the geometry of varieties.
A Nagata ring is a special type of ring in commutative algebra. More specifically, it is a class of rings that are defined in the context of properties related to integral closure and integral extensions.
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 \( x^n = 0 \).
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.
A **parafactorial local ring** is a specific type of local ring that possesses unique factorization properties in a manner that extends the concept of unique factorization in integers or principal ideal domains (PIDs). To understand a parafactorial local ring, let's start breaking down the key components involved: 1. **Local Ring**: A local ring is a ring that has a unique maximal ideal.
In the context of mathematics, particularly in abstract algebra, a **perfect ideal** is a concept that can arise in the theory of rings. However, the term "perfect ideal" is not standard and could be used in various contexts with slightly different meanings depending on the specific area of study.
In the context of ring theory, a branch of abstract algebra, a **primal ideal** typically refers to a specific type of ideal in a commutative ring. However, the term can sometimes lead to confusion, as its definition can vary slightly depending on the context or the source.
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.
In ring theory, a branch of abstract algebra, a **primary ideal** is a specific type of ideal that has certain properties related to the concept of prime ideals.
In the context of abstract algebra, specifically in ring theory, a principal ideal is a specific type of ideal in a ring that can be generated by a single element. Formally, let \( R \) be a ring and let \( a \) be an element of \( R \).
A **Principal Ideal Domain (PID)** is a special type of integral domain in the field of abstract algebra. Here are some key characteristics of a PID: 1. **Integral Domain**: A PID is an integral domain, which means it is a commutative ring with no zero divisors and has a multiplicative identity (usually denoted as 1). 2. **Principal Ideals**: In a PID, every ideal is a principal ideal.
A **principal ideal ring** (PIR) is a type of ring in which every ideal is a principal ideal. This means that for any ideal \( I \) in the ring \( R \), there exists an element \( r \in R \) such that \( I = (r) = \{ r \cdot a : a \in R \} \). In other words, each ideal can be generated by a single element.
A Prüfer domain is a type of integral domain that generalizes the notion of a Dedekind domain. It is defined as an integral domain \( D \) in which every finite non-zero torsion-free ideal is a projective module. This property is very similar to that of Dedekind domains, which states that every non-zero fractional ideal is a projective \( D \)-module.
A Puiseux series is a type of power series that allows for fractional exponents and is used in algebraic geometry and the study of singularities. It can be thought of as a generalization of the Taylor series or Laurent series.
A quasi-homogeneous polynomial is a type of polynomial that exhibits a certain kind of symmetry in terms of its variable degrees. Specifically, a polynomial \( f(x_1, x_2, \ldots, x_n) \) is called quasi-homogeneous of degree \( d \) if it can be expressed as a sum of terms, each of which has the same "weighted degree".
The Rabinowitsch trick is a technique used in number theory, particularly in the field of algebraic number theory and in the study of polynomial divisibility. It is named after the mathematician Solomon Rabinowitsch. The trick primarily involves the manipulation of polynomials to demonstrate certain divisibility properties. Specifically, it is often applied in the context of proving that a polynomial is divisible by another polynomial under certain conditions.
Rees algebra is a construction in commutative algebra that generalizes the notion of an ideal in a ring. It is particularly useful in the study of local rings and algebraic geometry. The Rees algebra is named after David Rees, who introduced it as a tool for the study of properties of ideals and their associated varieties.