Hilbert Basis Theorem

Theorem: If \(R\) is a polynomial ring in finitely many variables over a field or over the ring of integers, then every ideal in \(R\) can be generated by finitely many elements. Theorem: If a ring \(R\) is Noetherian, then the polynomial ring \(R[x]\) is Noetherian.

Proof

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For finitely generated algebras:

attachments/Pasted%20image%2020220203135730.png # Notes

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As a consequence, affine or projective spaces with the Zariski topology are Noetherian topological spaces, which implies that any closed subset of these spaces is compact.