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In ring theory, a branch of mathematics, a radical of a ring is an ideal of "not-good" elements of the ring. The first example of a radical was the nilradical introduced by Köthe (1930), based on a suggestion of Wedderburn (1908). In the next few years several other radicals were discovered, of which the most important example is the Jacobson ...
For a general ring with unity R, the Jacobson radical J(R) is defined as the ideal of all elements r ∈ R such that rM = 0 whenever M is a simple R-module.That is, = {=}. This is equivalent to the definition in the commutative case for a commutative ring R because the simple modules over a commutative ring are of the form R / for some maximal ideal of R, and the annihilators of R / in R are ...
In other words: "The only element of a Noetherian ring in all powers of J is 0." The original conjecture posed by Jacobson in 1956 [ 1 ] asked about noncommutative one-sided Noetherian rings, however Israel Nathan Herstein produced a counterexample in 1965, [ 2 ] and soon afterwards, Arun Vinayak Jategaonkar produced a different example which ...
Consider the ring of integers.. The radical of the ideal of integer multiples of is (the evens).; The radical of is .; The radical of is .; In general, the radical of is , where is the product of all distinct prime factors of , the largest square-free factor of (see Radical of an integer).
Radical expression involving roots, also known as an nth root; Radical symbol (√), used to indicate the square root and other roots; Radical of an algebraic group, a concept in algebraic group theory; Radical of an ideal, an important concept in abstract algebra; Radical of a ring, an ideal of "bad" elements of a ring
The factor ring of a radical ideal is a semiprime ring for general rings, and is a reduced ring for commutative rings. Primary ideal : An ideal I is called a primary ideal if for all a and b in R , if ab is in I , then at least one of a and b n is in I for some natural number n .
Let R be a ring (with unity) and let r be an element of R.Then r is said to be quasiregular, if 1 − r is a unit in R; that is, invertible under multiplication. [1] The notions of right or left quasiregularity correspond to the situations where 1 − r has a right or left inverse, respectively.
A ring R is called a Jacobson ring if the nilradical and Jacobson radical of R/P coincide for all prime ideals P of R. An Artinian ring is Jacobson, and its nilradical is the maximal nilpotent ideal of the ring. In general, if the nilradical is finitely generated (e.g., the ring is Noetherian), then it is nilpotent.