Valuation rings as limits of complete intersection rings
Simion Stoilow Institute of Mathematics of the Romanian Academy(罗马尼亚科学院西奥多·斯托伊洛数学研究所);University of Bucharest, Faculty of Mathematics and Computer Science(布加勒斯特大学数学与计算机科学系)
We give three proofs that valuation rings are derived splinters: a geometric proof using the absolute integral closure, a homological proof which reduces the problem to checking that valuation rings are splinters (which is done in the second author's PhD thesis and which we reprise here), and a proof by approximation which reduces the problem to Bhatt's proof of the derived direct summand conjecture. The approximation property also shows that smooth algebras over valuation rings are splinters.
Using a local monomialization result of Knaf and Kuhlmann, we prove that the valuation ring of an Abhyankar valuation of a function field over a perfect ground field of prime characteristic is Frobenius split. We show that a Frobenius splitting of a sufficiently well-behaved center lifts to a Frobenius splitting of the valuation ring. We also investigate properties of valuations centered on arbitrary Noetherian domains of prime characteristic. In contrast to [arXiv:1507.06009], this paper emphasizes the role of centers in controlling Frobenius properties of valuations rings in prime characteri…
Let $K$ be a characteristic zero algebraic function field with a valuation $ν$. Let $L$ be a finite extension of $K$ and $ω$ be an extension of $ν$ to $L$. We establish that the valuation ring $V_ω$ of $ω$ is essentially finitely generated over the valuation ring $V_ν$ of $ν$ if and only if the initial index $ε(ω|ν)$ is equal to the ramification index $e(ω|ν)$ of the extension. This gives a positive answer, for characteristic zero algebraic function fields, to a question posed by Hagen Knaf.
Let $(K,v)$ be a valued field. We review some results of MacLane and Vaquié on extensions of $v$ to valuations on the polynomial ring $K[x]$. We introduce certain MacLane-Vaquié chains of residually transcendental valuations, and we prove that every valuation $μ$ on $K[x]$ is a limit of a finite or countably infinite MacLane-Vaquié chain. This chain underlying $μ$ is essentially unique and contains arithmetic data yielding an explicit description of the graded algebra of $μ$ as an algebra over the graded algebra of $v$.
Let A and B be integral domains. Suppose A is Noetherian and B is a finitely generated A-algebra that contains A. Denote by A' the integral closure of A in B. We show that A' is determined by finitely many unique discrete valuation rings. Our result generalizes Rees' classical valuation theorem for ideals. We also obtain a variant of Zariski's main theorem.
Algebraic valuation ring extensions as limits of complete intersection algebras
Simion Stoilow Institute of Mathematics of the Romanian Academy(罗马尼亚科学院西蒙·斯托伊洛数学研究所);University of Bucharest, Faculty of Mathematics and Computer Science(布加勒斯特大学数学与计算机科学系)
In this paper, we study the structure of the graded ring associated to a limit key polynomial $Q_n$ in terms of the key polynomials that define $Q_n$. In order to do that, we use direct limits. In general, we describe the direct limit of a family of graded rings associated to a totally ordered set of valuations. As an example, we describe the graded ring associated to a valuation-algebraic valuation as a direct limit of graded rings associated to residue-transcendental valuations.
Étant donné un anneau de valuation $V$, de corps résiduel $F$ et de groupe des valeurs $Γ$, on donne une condition suffisante pour qu'un anneau local dominant $V$ soit un anneau de valuation de groupe $Γ$. Lorsque $V$ contient un corps $k$, ce résultat est appliqué à la construction d'un anneau de valuation contenant $V$ et une extension donnée $k'$ de $k$, de groupe $Γ$ et de corps résiduel engendré par $k'$ et $F$. Cela s'avère possible, notamment, lorsque $k'$ ou $F$ est séparable sur $k$. Given a valuation ring $V$, with residue field $F$ and value group $Γ$, we give a sufficient condition…
In this paper we prove that the Hermite ring conjecture holds for valuation rings $V$, and the special liner group $SL_n(V[x])$ coincides with the group generated by elementary matrices $E_n(V[x])$ for $n\geq3$. For any arithmetical ring $R$ and $n\geq3$, we show $SL_n(R[x]) = SL_n(R)\cdot E_n(R[x])$.
Compatibility of quasi-orderings and valuations; A Baer-Krull Theorem for quasi-ordered Rings
在他1969年的作品中,Merle E. Manis在交换环上引入了赋值。最近,第二作者发展了全拟序环类。在本文中,我们建立了环上的赋值与拟序之间的相容性概念,从而定义了拟序环的秩。进一步证明了拟序环的Baer-Krull定理:若R上有一个Manis赋值v,则R的所有v相容拟序都是通过将拟序从剩余类环提升到R本身来刻画的.
We describe the immediate extensions of a one dimensional valuation ring $V$ which could be embedded in some separation of a ultrapower of $V$ with respect to a certain ultrafilter. For such extensions holds a kind of Artin's approximation.
Valuation rings of mixed characteristic as limits of complete intersection rings
Simion Stoilow Institute of Mathematics of the Romanian Academy(罗马尼亚科学院西蒙·斯托伊洛数学研究所);University of Bucharest, Faculty of Mathematics and Computer Science(布加勒斯特大学数学与计算机科学系)
Let K be a field with a valuation $ν$ and let L = K(x) be a transcendental extension of K, then any valuation $μ$ of L which extends $ν$ is determined by its restriction to the polynomial ring K[x]. We know how to associate to this valuation $μ$ a family of valuations A = ($μ$i)i$\in$I of K[x], called the associated admise family, which converges in a certain sense towards the valuation $μ$. Although the definition of this family, as well as the notion of convergence, essentially imply the structure of the polynomial ring, in particular the degree of polynomials, we show in this note that the …
The main goal of this paper is to study some properties of an extension of valuations from classical invariants. More specifically, we consider a valued field $(K,ν)$ and an extension $ω$ of $ν$ to a finite extension $L$ of $K$. Then we study when the valuation ring of $ω$ is essentially finitely generated over the valuation ring of $ν$. We present a necessary condition in terms of classic invariants of the extension by Hagen Knaf and show that in some particular cases, this condition is also sufficient. We also study when the corresponding extension of graded algebras is finitely generated. F…
我们考虑的问题是,哪些半群可以出现作为半群$S_R(ν)$的秩1赋值控制的诺特局部环$R$的正值。从$P_R(n)$的上界开始,给出了$n\in\NN$的$ϕ(n)=S_R(ν)\cap (0,n)$增长的多项式型上界,其中$P_R(n)$是$R$的Hilbert函数.在Cutkosky和Teissier的论文“Semigroups of valuations on local rings,II”中,这个界被推广到任意秩赋值的一个非常一般的界,arXiv:0805.3788。这个界已经足以给出秩1良序半群的简单例子,这些半群不是控制诺特局部环的赋值的值半群$S_R(ν)$。在秩为1的情况下,有可能给出更精确的估计$ϕ(n)$,我们证明在本文中。我们还给出的例子表明,许多不同的增长率是可能的$ϕ(n)$在一个经常的本地环的尺寸2,如$n(α$的任何合理的$α$与$1\leα\le 2$,和$n{log}(n)$。
We show how several results about p-adic lattices generalize easily to lattices over valuation ring of arbitrary rank having only the Henselian property for quadratic polynomial. If 2 is invertible we obtain the uniqueness of the Jordan decomposition and the Witt Cancelation Theorem. We show that the isomorphism classes of indecomposable rank 2 lattices over such a ring in which 2 is not invertible are characterized by two invariants, provided that the lattices contain a primitive norm divisible by 2 of maximal valuation.
Extension of valuation rings as limits of complete intersection algebras
Simion Stoilow Institute of Mathematics of the Romanian Academy(罗马尼亚科学院西奥多·斯托伊洛数学研究所);University of Bucharest, Faculty of Mathematics and Computer Science(布加勒斯特大学数学与计算机科学系)
This is an extended introduction to discrete valuation rings and Dedekind domains. Some natural generalizations of Dedekind domains are also (briefly) discussed including "almost Dedekind domains", Prüfer domains, Krull domains, and singular integral domains of dimension 1.