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Associated Graded Module


The associated graded module of a module M over a commutative unit ring R, with respect to a filtration

 F:... subset= I_2 subset= I_1 subset= I_0=R
(1)

of ideals of R, is

 gr_F(M)=I_0M/I_1M direct sum I_1M/I_2M direct sum I_2M/I_3M direct sum ...,
(2)

which is a graded module over the associated graded ring gr_F(R). Addition is defined componentwise. For a in I_i and m in I_jM, the residue class of a in I_i/I_(i+1) sends the residue class of m in I_jM/I_(j+1)M to the residue class of am in I_(i+j)M/I_(i+j+1)M.

If I is a proper ideal of R, then the notation gr_I(M) indicates the associated graded module of M with respect to the I-adic filtration of R,

 gr_I(M)=M/IM direct sum IM/I^2M direct sum I^2M/I^3M direct sum ....
(3)

See also

Associated Graded Ring, Associated Graded Space, Hilbert-Samuel Function, Rees Module

Portions of this entry contributed by Margherita Barile

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References

Bruns, W. and Herzog, J. Cohen-Macaulay Rings, 2nd ed. Cambridge, England: Cambridge University Press, 1993.

Referenced on Wolfram|Alpha

Associated Graded Module

Cite this as:

Weisstein, Eric W., with contributions by Margherita Barile. "Associated Graded Module." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/AssociatedGradedModule.html

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