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Perfect ideal

From Wikipedia, the free encyclopedia

In commutative algebra, a perfect ideal is a proper ideal in a Noetherian ring such that its grade equals the projective dimension of the associated quotient ring.[1]

A perfect ideal is unmixed.

For a regular local ring a prime ideal is perfect if and only if is Cohen-Macaulay.

The notion of perfect ideal was introduced in 1913 by Francis Sowerby Macaulay[2] in connection to what nowadays is called a Cohen-Macaulay ring, but for which Macaulay did not have a name for yet. As Eisenbud and Gray[3] point out, Macaulay's original definition of perfect ideal coincides with the modern definition when is a homogeneous ideal in polynomial ring, but may differ otherwise. Macaulay used Hilbert functions to define his version of perfect ideals.

References

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  1. ^ Matsumura, Hideyuki (1987). Commutative Ring Theory. Cambridge: Cambridge University Press. p. 132. ISBN 9781139171762.
  2. ^ Macaulay, F. S. (1913). "On the resolution of a given modular system into primary systems including some properties of Hilbert numbers". Math. Ann. 74 (1): 66–121. doi:10.1007/BF01455345. S2CID 123229901. Retrieved 2023-08-06.
  3. ^ Eisenbud, David; Gray, Jeremy (2023). "F. S. Macaulay: From plane curves to Gorenstein rings". Bull. Amer. Math. Soc. 60 (3): 371–406. doi:10.1090/bull/1787. Retrieved 2023-08-06.