Solving homogeneous linear equations over polynomial semirings
| Autor: | Dong, Ruiwen |
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| Rok vydání: | 2022 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | For a subset $B$ of $\mathbb{R}$, denote by $\operatorname{U}(B)$ be the semiring of (univariate) polynomials in $\mathbb{R}[X]$ that are strictly positive on $B$. Let $\mathbb{N}[X]$ be the semiring of (univariate) polynomials with non-negative integer coefficients. We study solutions of homogeneous linear equations over the polynomial semirings $\operatorname{U}(B)$ and $\mathbb{N}[X]$. In particular, we prove local-global principles for solving single homogeneous linear equations over these semirings. We then show PTIME decidability of determining the existence of non-zero solutions over $\mathbb{N}[X]$ of single homogeneous linear equations. Our study of these polynomial semirings is largely motivated by several semigroup algorithmic problems in the wreath product $\mathbb{Z} \wr \mathbb{Z}$. As an application of our results, we show that the Identity Problem (whether a given semigroup contains the neutral element?) and the Group Problem (whether a given semigroup is a group?) for finitely generated sub-semigroups of the wreath product $\mathbb{Z} \wr \mathbb{Z}$ is decidable when elements of the semigroup generator have the form $(y, \pm 1)$. Comment: 21 pages including appendix, 1 figure |
| Databáze: | arXiv |
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