Let b,c be a system of
parameters in a 2-dimensional local (Noetherian) domain (R,M). For n ≧ 0,
the chain (bn : 1) ⊂ (bn : c) ⊂ (bn : c2) ⊂⋯ becomes stable. Thus define a
function S(b,c,−) by letting S(b,c,n) be the least integer k ≧ 0 such that
(bn : ck) = (bn : ck+1). Ratliff has shown that R is unmixed if and only if S(b,c,−) is
bounded. This paper shows that if R is unmixed then for any 0≠d ∈ M there
is an integer ∗d ≧ 0 such that for any system of parameters b,c and any
i ≧ 0,S(b,c,∗b + i) = ∗c.
|