Prime ideal

Prime order of an ideal

Let 𝑅 be a commutative ring, 𝔭 be a prime ideal, and 𝔞 be an ideal. Then ord𝔭(𝔞) is the largest 𝑚 0 such that 𝔭𝑚 𝔞, #m/def/ring see product ideal.1 For 𝛼 𝑅, we also write ord𝔭(𝛼) :=ord𝔭(𝛼).

Properties

  1. ord𝔭(𝔞𝔟) ord𝔭(𝔞) +ord𝔭(𝔟), which becomes an equality if 𝑅 admits UFI.


#state/tidy | #lang/en | #SemBr

Footnotes

  1. 2022. Algebraic number theory course notes, p. 26