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quotient module (Definition)

Let $ M$ be a module over a ring $ R$, and let $ S$ be a submodule of $ M$. The quotient module $ M/S$ is the quotient group $ M/S$ with scalar multiplication defined by $ \lambda(x+S)=\lambda x+S$ for all $ \lambda\in R$ and all $ x\in M$.

This is a well defined operation. Indeed, if $ x+S = x'+S$ then for some $ s\in S$ we have $ x'=x+s$ and therefore

$\displaystyle \lambda x'$ $\displaystyle = \lambda(x+s)$    
  $\displaystyle = \lambda x+\lambda s$    

so that $ \lambda x' + S = \lambda x + \lambda s + S = \lambda x + S$, since $ \lambda s \in S$.

In the special case that $ R$ is a field this construction defines the quotient vector space of a vector space by a vector subspace.



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"quotient module" is owned by rspuzio. [ full author list (3) | owner history (2) ]
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Also defines:  quotient vector space
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Cross-references: vector subspace, vector space, field, operation, well defined, multiplication, scalar, quotient group, submodule, ring, module
There are 9 references to this entry.

This is version 6 of quotient module, born on 2003-10-15, modified 2006-07-29.
Object id is 4966, canonical name is QuotientModule.
Accessed 3453 times total.

Classification:
AMS MSC16D10 (Associative rings and algebras :: Modules, bimodules and ideals :: General module theory)

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