Semisimple Artinian ring: Difference between revisions

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==Definition for commutative rings==
{{curing property}}
==Definition==


===Symbol-free definition===
===Symbol-free definition===


A [[commutative unital ring]] (or any [[commutative ring]]) is termed '''semisimple''' if it satisfies the following equivalent conditions:
A [[commutative unital ring]] is termed '''semisimple Artinian''' if it satisfies the following equivalent conditions:


* The [[Jacobson radical]] (viz the intersection of its [[maximal ideal]]s) is trivial
* Every module over it is [[semisimple module|semisimple]]
* It is a [[subdirect product]] of fields
* Every module over it is [[projective module|projective]]
* It is a [[direct product]] of fields
* Every module over it is [[injective module|injective]]
* Every short exact sequence of modules over it, splits
* Its [[global dimension]] is zero
* The ring is semisimple as a module over itself
* The ring is a direct product of finitely many fields


==Definition for noncommutative rings==
==Relation with other properties==


===Symbol-free definition===
===Stronger properties===
 
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A [[unital ring]] (or any [[ring]]) is termed '''semisimple''' if it satisfies the following equivalent conditions:
* [[Field]]


* The intersection of all its [[maximal left ideal]]s is trivial
===Weaker properties===
* The intersection of all its [[maximal right ideal]]s is trivial


[[Category: Properties of noncommutative rings]]
* [[Artinian ring]]
* [[Zero-dimensional ring]]
* [[Semiprimitive ring]]: (some people use the term '''semisimple''' for such a ring)

Latest revision as of 16:34, 12 May 2008

This article defines a property of commutative unital rings; a property that can be evaluated for a commutative unital ring
View all properties of commutative unital rings
VIEW RELATED: Commutative unital ring property implications | Commutative unital ring property non-implications |Commutative unital ring metaproperty satisfactions | Commutative unital ring metaproperty dissatisfactions | Commutative unital ring property satisfactions | Commutative unital ring property dissatisfactions

Definition

Symbol-free definition

A commutative unital ring is termed semisimple Artinian if it satisfies the following equivalent conditions:

  • Every module over it is semisimple
  • Every module over it is projective
  • Every module over it is injective
  • Every short exact sequence of modules over it, splits
  • Its global dimension is zero
  • The ring is semisimple as a module over itself
  • The ring is a direct product of finitely many fields

Relation with other properties

Stronger properties

Weaker properties