In this paper, we study some connections between the polynomial ring $R[y]$ and the differential polynomial ring $R[x;D]$ . In particular, we answer a question posed by Smoktunowicz, which asks whether $R[y]$ is nil when $R[x;D]$ is nil, provided that $$R$$ is an algebra over a field of positive characteristic and $$D$$ is a locally nilpotent derivation.
more »
« less
Formation, structure and climatic significance of blue rings and frost rings in high elevation bristlecone pine (Pinus longaeva D.K. Bailey)
An official website of the United States government

