An essential right ideal intersects every nonzero right ideal nontrivially. A regular element of a ring is a two-sided non-zero-divisor: both and imply . Writing for the set of these elements, the classical right ring of quotients is a ring containing , with every invertible and every element of expressible as .
Goldie theorem states that a semiprime ring has a semisimple Artinian classical right ring of quotients if and only if it is a right Goldie ring: it satisfies the ascending chain condition on right annihilators and has finite uniform dimension. In particular, every semiprime ring that is a right Noetherian ring satisfies the theorem. We prove the requested case directly using the supplied assumption about essential right ideals.
First let . If a nonzero right ideal had , the sum
would be direct. Indeed, a finite relation gives , hence ; cancellation of repeats the argument. Each is a nonzero right ideal, so the partial sums form a strictly ascending chain. This contradicts right Noetherianity. Thus a regular principal right ideal in a right Noetherian ring is essential, and every right ideal containing is essential.
For and , put
This is an essential right ideal. To check this, take a nonzero right ideal . If , then . Otherwise is a nonzero right ideal, so it meets nontrivially; lifting an element of that intersection gives a nonzero element of . By the supplied assumption, contains some , giving
This is the right Ore condition. The set is multiplicatively closed, and the denominator cancellation condition holds because its elements are non-zero-divisors. Therefore Ore theorem constructs and embeds in it.
For every right ideal of ,
Indeed, if , then . Contracting an ascending chain of right ideals of to therefore proves that is a right Noetherian ring.
Suppose is an essential right ideal of . For a nonzero right ideal of , choose . The right Ore condition gives a common right denominator for a finite expression of in , so there is with
Thus is an essential right ideal of . It contains a regular element of a ring, which becomes a unit in , and consequently .
Finally, for any right ideal of , choose by Zorn lemma a right ideal maximal subject to . Then is essential: a nonzero right ideal disjoint from would enlarge while keeping it disjoint from . Hence . Every submodule of the right regular module has a complement, making it a semisimple module. Since it is also Noetherian, it is a finite direct sum of simple modules. It is therefore Artinian, and is a semisimple Artinian ring. This is semisimplicity of a classical quotient from regular elements in essential ideals.