In a commutative Noetherian ring with identity, it is proven that the ring $R$ is not isomorphic to the polynomial ring $R[x]$. An example illustrates that this result fails if $R$ is not Noetherian, highlighting the importance of the Noetherian condition. Participants discuss various attempts to prove the isomorphism and identify common mistakes in reasoning. The conversation emphasizes the necessity of understanding the properties of Noetherian rings in relation to polynomial rings. Ultimately, the distinction between Noetherian and non-Noetherian rings is crucial for this theorem.
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chuyenvien94
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Let $R$ be a commutative Noetherian ring with identity. Prove that $R\ncong R\left[x\right]$ and give an example that the result is not true if $R$ is not Noetherian.
Hello!
In one book I saw that function ##V## of 3 variables ##V_x, V_y, V_z## (vector field in 3D) can be decomposed in a Taylor series without higher-order terms (partial derivative of second power and higher) at point ##(0,0,0)## such way:
I think so: higher-order terms can be neglected because partial derivative of second power and higher are equal to 0. Is this true?
And how to define vector field correctly for this case? (In the book I found nothing and my attempt was wrong...