On the difference between `tropical functions' and real-valued functions

亚环面微分代数的基本定理与非阿基米德微分方程的收敛半径

The Fundamental theorem of tropical differential algebra over nontrivially valued fields and the radius of convergence of nonarchimedean differential equations

本文证明了亚环面微分方程的基本定理，扩展了已有的结果，展示了如何通过热带方法计算非平凡赋值域上微分方程解的收敛半径。

Krull-tropical hypersurfaces

The concepts of tropical-semiring and tropical hypersurface, are extended for an arbitrary ordered group. Then, we define the tropicalization of a polynomial with coefficients in a Krull-valued field. After a close study of the properties of the operator "tropicalization" we conclude with an extension of Kapranov's theorem to algebraically closed fields together with a valuation over an ordered group.

分次Betti数不是热带不变量

The graded Betti numbers are not tropical invariants

该研究证明分次Betti数不是齐次理想或赋值域上射影代数概形热带化的不变量，通过构造一组对应同一热带理想但Betti表不同的饱和理想完成论证。

Universal valued fields and lifting points in local tropical varieties

Let $k$ be a field with a real valuation $ν$ and $R$ a $k$-algebra. We show that there exist a $k$-algebra $K$ and a real valuation $μ$ on $K$ extending $ν$ such that any real ring valuation of $R$ is induced by $μ$ via some homomorphism from $R$ to $K$; $K$ can be chosen to be a field. Then we study the case when $ν$ is trivial and $R$ a complete local Noetherian ring with the residue field $k$. Let $K$ be the ring $\bar{k}[[t^\R]]$ of Hahn series with its natural valuation $μ$; $\bar{k}$ is an algebraic closure of $k$. Despite $K$ is not universal in the strong sense defined above, it has th…

A Newton Polygon Rule for Formally-Real Valued Fields and Multiplicities over the Signed Tropical Hyperfield

By defining multiplicities for zeros of polynomials over hyperfields, Baker and Lorscheid were able to provide a unifying perspective on Descartes's rule and the Newton polygon rule for polynomials over a formally-real and valued field respectively. In this paper, we apply their multiplicity formula to the hyperfield associated with formally-real, valued fields to prove a Newton polygon rule which combines Descartes's rule of signs with the classical Newton polygon rule.

Integer-valued polynomials over matrices and divided differences

Let $D$ be an integrally closed domain with quotient field $K$ and $n$ a positive integer. We give a characterization of the polynomials in $K[X]$ which are integer-valued over the set of matrices $M_n(D)$ in terms of their divided differences. A necessary and sufficient condition on $f\in K[X]$ to be integer-valued over $M_n(D)$ is that, for each $k$ less than $n$, the $k$-th divided difference of $f$ is integral-valued on every subset of the roots of any monic polynomial over $D$ of degree $n$. If in addition the intersection of the maximal ideals of finite index is $(0)$ then it is sufficie…