Standard Lemma guide

semisimple

adj · 8 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

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Pronunciation

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1

adj

Meaning 1

In any of several technical senses, decomposable into sub-objects that have a simple structure.

Containing a collection of simple objects such that all objects in the category are direct sums of these simple objects.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Qualifier: most generally

Topics: algebra, category-theory, computing, engineering, mathematics, natural-sciences, physical-sciences, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

2

adj

Meaning 2

In any of several technical senses, decomposable into sub-objects that have a simple structure.

In which each submodule is a direct summand; equivalently, equal to a direct sum of simple submodules.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Qualifier: module theory

Topics: algebra, mathematics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

3

adj

Meaning 3

In any of several technical senses, decomposable into sub-objects that have a simple structure.

Semisimple as a module over itself; equivalently, such that all (left) modules are semisimple.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Qualifier: ring theory

Topics: algebra, mathematics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

4

adj

Meaning 4

In any of several technical senses, decomposable into sub-objects that have a simple structure.

Semisimple as a module over itself; equivalently, such that all (left) modules are semisimple.

Semiprimitive: having trivial Jacobson radical.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable, proscribed

Qualifier: ring theory

Topics: algebra, mathematics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: Jacobson semisimple

Antonyms: none provided

5

adj

Meaning 5

In any of several technical senses, decomposable into sub-objects that have a simple structure.

For which every invariant subspace has an invariant complement, equivalent to the minimal polynomial being squarefree.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Topics: algebra, linear-algebra, mathematics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

6

adj

Meaning 6

In any of several technical senses, decomposable into sub-objects that have a simple structure.

Being a direct sum of simple Lie algebras.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Qualifier: Lie theory

Topics: algebra, mathematics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

7

adj

Meaning 7

In any of several technical senses, decomposable into sub-objects that have a simple structure.

Being a direct sum of simple representations (also known as irreducible representations).

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Qualifier: representation theory

Topics: algebra, mathematics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

8

adj

Meaning 8

In any of several technical senses, decomposable into sub-objects that have a simple structure.

Being a linear algebraic group whose radical of the identity component is trivial.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Topics: algebra, group-theory, mathematics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

History

Etymology

From semi- + simple.