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Studies in Rings generalised Unique Factorisation Rings

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-85-<br />

Theorem 3.29.<br />

Let R be a Noetherian r<strong>in</strong>g with many normal<br />

eleme nts and T be the partial quo tiffi t r<strong>in</strong>g of R<br />

at C =(a € R/a is normal)<br />

. Then for any z <strong>in</strong> T and<br />

x c: C, there is ~, an element u such that z + ux is<br />

weakly T-<strong>in</strong>vertible.<br />

Proof:<br />

By remark 3.~4, T is an over-r<strong>in</strong>g of Rand T<br />

has only a f<strong>in</strong>ite number of maximal idealso<br />

Let ~ = [M/M is a maximal ideal of T with z e M]<br />

and ~. = (M/M is a maximal ideal of T with z ~ M]<br />

Then ..0 and ill are f<strong>in</strong>ite collections of prime ideals<br />

and nei the r M S. M I nor M' ~ M for any 1\1 E ~ and ~~lEd'<br />

as they are ma~imal idealso Thus by theorem 3.26, there<br />

exists an element u 6: M, for all M E AI and u tf. M<br />

for any M€ A • Then the eleme nt z+ux ~ M for any maximal<br />

ideal of To For, if z+ux c M for some M€Ll, then<br />

z+ux-z ux<br />

..<br />

t:;<br />

= M. But x

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