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Studies in Rings generalised Unique Factorisation Rings

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-38-<br />

Let R be a GUFR with over-r<strong>in</strong>g S. We shall make<br />

use of a certa<strong>in</strong> p a r t i a I quo t i en t r<strong>in</strong>g of R. Let<br />

C =[a€ R/aR = Ra is S-<strong>in</strong>vertjble}. We prove C consists<br />

of regular elements and C is a<br />

(right and left) Ore set.<br />

QUOTIENT RINGS<br />

Theorem 2 0 6 .<br />

Let R be a GUFR with the over-r<strong>in</strong>g S. Then C<br />

conta<strong>in</strong>s only regulor elements and C is an Ore set.<br />

Proof<br />

Let a E: C, we provelR( a) = r R( a) = o. S<strong>in</strong>c e<br />

a f e, aR = Ra is S-<strong>in</strong>vertible and so there exists an<br />

R-subbimodule 1- 1 of 5 such that (aR)1- 1 = 1- 1(aR) = R.<br />

Thus we can f<strong>in</strong>d elements r i<br />

c R, si ( 1- l f 5 for<br />

i=1,2, •.. ,n, such that<br />

which implies<br />

n<br />

n<br />

L (ar.)s. = 1. iAe<br />

1=<br />

· 1 1 1<br />

n<br />

a l: r.s.=l<br />

· 1 l 1.<br />

fS(a E r.s.) = lS(l)=O and consequently<br />

. 11.1<br />

1=<br />

n<br />

1=<br />

lR (a) ~<br />

r R<br />

(a) = o.<br />

~ (a)<br />

< ls( a L r.s.) = I S<br />

( l ) = o. Similarly<br />

- · 111<br />

1=<br />

For the second part of the theorem, let a,b e C,<br />

then aR=Ra and bR = Rb. Now abR = a(Rb) = Rabo S<strong>in</strong>ce

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