Math 2.0

Associative rings and algebras Definition

Semiprimitive ring

Builds on RingJacobson radicalLeft ideal

Definition

Let RR be a ring with identity. RR is semiprimitive if its Jacobson radical J(R)J(R), the intersection of all maximal left ideals of RR, is 00.

Remarks

Example: ℤ\Z is semiprimitive, since its maximal ideals are pℤp\Z for primes pp and ⋂ppℤ=0\bigcap_p p\Z = 0. Non-example: the local ring ℤ(p)\Z_{(p)} of fractions with denominator prime to pp is not semiprimitive, since J(ℤ(p))=pℤ(p)≠0J(\Z_{(p)}) = p\Z_{(p)} \ne 0. Equivalently, RR is a subdirect product of left primitive rings, or RR has a faithful semisimple left module. The definition is left-right symmetric, because J(R)J(R) is also the intersection of the maximal right ideals. Other names are Jacobson semisimple and J-semisimple.

Reading path

To understand this page from the ground up, read these 5 pages in order. The foundations come first.

Show the path as a graph
Each page uses the pages above it. The colour of the bar on a box shows how strong the evidence is, and the box also gives it as text. The list has the same pages.
  • no evidence level
  1. Group concept
  2. Jacobson radical concept
  3. Left ideal concept
  4. Ring definition
  5. Semiprimitive ring definition

Further reading

  1. Web https://en.wikipedia.org/wiki/Semiprimitive_ring
About this page
TagTMKXXG8XHR
URIm2://TMKXXG8XHR
Kinddefinition
WritingW0 stub
MSC16N20
DefinesSemiprimitive ring
UsesRing, Jacobson radical, Left ideal
Changed2 November 2026

Markdown · JSON · Edit on GitHub

What this page needs for W1

  • an inventory row: the row of the inventory that the node accounts for (0 of 1)
  • a source with a locator (0 of 1)

The writing levels say how complete the text of a page is. They do not measure its truth.

What links here

No page links to this page yet.