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arXiv · 1806.03545

Tensor-Multinomial Sums of Ideals: Primary Decompositions and Persistence of Associated Primes

Irena Swanson·Robert M. Walker
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Abstract

Given a polynomial ring $C$ over a field and proper ideals $I$ and $J$ whose generating sets involve disjoint variables, we determine how to embed the associated primes of each power of $I+J$ into a collection of primes described in terms of the associated primes of select powers of $I$ and of $J$. We record two applications. First, in case the field is algebraically closed, we construct primary decompositions for powers of $I+J$ from primary decompositions for powers of $I$ and $J$. Separately, we attack the persistence problem for associated primes of powers of an ideal in case one of $I$ or $J$ is a non-zero normal ideal.

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Irena Swanson, Robert M. Walker. 2018-06-09. Tensor-Multinomial Sums of Ideals: Primary Decompositions and Persistence of Associated Primes. https://doi.org/10.1090/proc/14630

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