Let aA, and suppose that a has a (minimal) primary decomposition. Then Ass(A/q) is 1;;non-empty/finite. Moreover, if a=q1qn, is a minimal primary decomposition, then:

{r(q1),,r(qn)}=Ass(A/a)

PROOF:

  1. There exists xqi, for example 1A. For such an x, we have r(a:x)=i=1nr(qi:x)=i=1npi, so by prime avoidance, there is some pi such that pi=r(a:x). This shows that 1;;{r(q1),,r(qn)}Ass(A/a)
  2. For the other direction, by minimality, we have for each i, an xijipjpi, and then r(a:xi)=pi.
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