abstract algebra, a module is indecomposable if it is non-zero and cannot be written as a direct sum of two non-zero submodules. Indecomposable is a weaker notion...
5 KB (705 words) - 22:27, 28 October 2023
simple module is indecomposable, but there are indecomposable modules that are not simple (e.g. uniform modules). Faithful A faithful module M is one...
22 KB (3,091 words) - 12:09, 26 March 2025
as module theory, a principal indecomposable module has many important relations to the study of a ring's modules, especially its simple modules, projective...
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mathematics: Indecomposable module, in algebra Indecomposable distribution, in probability Indecomposable continuum, in topology Indecomposability (intuitionistic...
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every injective module is uniquely a direct sum of indecomposable modules, and their structure is well understood. An injective module over one ring may...
28 KB (3,919 words) - 09:32, 15 February 2025
area of abstract algebra known as module theory, a semisimple module or completely reducible module is a type of module that can be understood easily from...
10 KB (1,249 words) - 15:50, 18 September 2024
R/(q_{i})} are indecomposable, so the primary decomposition is a decomposition into indecomposable modules, and thus every finitely generated module over a PID...
15 KB (2,160 words) - 10:01, 5 March 2025
module over itself and a module over Z. The rational numbers are algebraically compact as a Z-module. Together with the indecomposable finite modules...
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The simple modules are precisely the modules of length 1; this is a reformulation of the definition. Every simple module is indecomposable, but the converse...
9 KB (1,345 words) - 04:22, 19 May 2025
ring is semisimple if and only if every module over it is a semisimple module. An indecomposable module is a module that is not a direct sum of two nonzero...
15 KB (2,681 words) - 16:58, 23 January 2024
List of abstract algebra topics (section Module theory)
Localization of a module Completion (ring theory) Types Simple module, Semisimple module Indecomposable module Artinian module, Noetherian module Homological...
12 KB (1,129 words) - 10:50, 10 October 2024
indecomposable An indecomposable module is a non-zero module that cannot be written as a direct sum of two non-zero submodules. Every simple module is...
20 KB (2,611 words) - 18:28, 4 March 2025
Direct product (redirect from Direct product of modules)
^{n}} and R n . {\displaystyle \mathbb {R} ^{n}.} The direct product for modules (not to be confused with the tensor product) is very similar to the one...
16 KB (3,011 words) - 19:33, 2 June 2025
This allows them to derive relativistic wave equations. Simple module Indecomposable module Representation of an associative algebra Representation theory...
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combines several modules into a new, larger module. The direct sum of modules is the smallest module which contains the given modules as submodules with...
22 KB (3,536 words) - 22:52, 3 December 2024
maximal submodule, then M is a local module. M is also clearly a uniform module and thus is directly indecomposable. It is also easy to see that every finitely...
16 KB (2,263 words) - 23:51, 13 May 2025
Injective hull (redirect from Module of finite rank)
algebra, the injective hull (or injective envelope) of a module is both the smallest injective module containing it and the largest essential extension of...
8 KB (1,052 words) - 04:45, 13 December 2024
modules is injective. Every left injective module over a left Noetherian module can be decomposed as a direct sum of indecomposable injective modules...
20 KB (2,774 words) - 04:31, 7 July 2025
Fitting lemma (category Module theory)
basic statement in abstract algebra. Suppose M is a module over some ring. If M is indecomposable and has finite length, then every endomorphism of M...
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algebra, Kaplansky's theorem on projective modules, first proven by Irving Kaplansky, states that a projective module over a local ring is free; where a...
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Modular representation theory (category Module theory)
regular module). Each projective indecomposable module (and hence each projective module) in positive characteristic p may be lifted to a module in characteristic...
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Theorem (Lam 2001, §19): A module is said to be strongly indecomposable if its endomorphism ring is a local ring. For a module M {\displaystyle M} of finite...
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N_{2}/(N_{1}\cap N_{2})=\{0\}.} Uniserial modules are uniform, and uniform modules are necessarily directly indecomposable. Any commutative domain is a uniform...
9 KB (1,349 words) - 00:19, 7 May 2024
Tilting theory (redirect from Tilted module)
finite-dimensional algebras over k of global dimension ≤ 2 such that every indecomposable module either has projective dimension ≤ 1 or injective dimension ≤ 1....
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Associated prime (redirect from Coprimary module)
coprimary modules. For a one-sided Noetherian ring, there is a surjection from the set of isomorphism classes of indecomposable injective modules onto the...
6 KB (979 words) - 20:48, 5 March 2025
Endomorphism ring (category Module theory)
If the module is an injective module, then indecomposability is equivalent to the endomorphism ring being a local ring. For a semisimple module, the endomorphism...
9 KB (1,208 words) - 11:11, 3 December 2024
idempotent of a ring R is a nonzero idempotent a such that aR is indecomposable as a right R-module; that is, such that aR is not a direct sum of two nonzero...
19 KB (2,329 words) - 16:20, 26 June 2025
Krull–Schmidt theorem (category Module theory)
then E {\displaystyle E} is a direct sum of indecomposable modules. Up to a permutation, the indecomposable components in such a direct sum are uniquely...
9 KB (1,219 words) - 19:19, 24 May 2025
defined for modules over any integral domain, the case of abelian groups corresponding to modules over Z. For this, see finitely generated module#Generic...
7 KB (1,132 words) - 04:20, 31 March 2025
modules over some other rings. Specifically, if the endomorphism ring of the module M is local, then M is indecomposable; conversely, if the module M...
15 KB (2,300 words) - 20:46, 1 June 2025