scholarly journals Phase Transitions on C*-Algebras from Actions of Congruence Monoids on Rings of Algebraic Integers

2020 ◽  
Author(s):  
Chris Bruce
Keyword(s):  
Phase Transitions ◽  
Class Group ◽  
Number Fields ◽  
Algebraic Integers ◽  
Ring Of Integers ◽  
C Algebras ◽  
Rings Of Algebraic Integers ◽  
Beta 2 ◽  
Factor State ◽  
Type Classification

Abstract We compute the KMS (equilibrium) states for the canonical time evolution on C*-algebras from actions of congruence monoids on rings of algebraic integers. We show that for each $\beta \in [1,2]$, there is a unique KMS$_\beta $ state, and we prove that it is a factor state of type III$_1$. There are phase transitions at $\beta =2$ and $\beta =\infty $ involving a quotient of a ray class group. Our computation of KMS and ground states generalizes the results of Cuntz, Deninger, and Laca for the full $ax+b$-semigroup over a ring of integers, and our type classification generalizes a result of Laca and Neshveyev in the case of the rational numbers and a result of Neshveyev in the case of arbitrary number fields.

scholarly journals On the Steinitz module and capitulation of ideals

2000 ◽  
Vol 160 ◽  
pp. 1-15
Author(s):  
Chandrashekhar Khare ◽  
Dipendra Prasad
Keyword(s):  
Number Field ◽  
Algebraic Curve ◽  
Class Group ◽  
Algebraic Curves ◽  
Finite Extension ◽  
Number Fields ◽  
Line Bundles ◽  
Exterior Power ◽  
Ring Of Integers ◽  
And Function

AbstractLet L be a finite extension of a number field K with ring of integers and respectively. One can consider as a projective module over . The highest exterior power of as an module gives an element of the class group of , called the Steinitz module. These considerations work also for algebraic curves where we prove that for a finite unramified cover Y of an algebraic curve X, the Steinitz module as an element of the Picard group of X is the sum of the line bundles on X which become trivial when pulled back to Y. We give some examples to show that this kind of result is not true for number fields. We also make some remarks on the capitulation problem for both number field and function fields. (An ideal in is said to capitulate in L if its extension to is a principal ideal.)

The Kernel of and the 4-Rank of K2(O)

1992 ◽  
Vol 35 (3) ◽  
pp. 295-302 ◽  
Author(s):  
Ruth I. Berger
Keyword(s):  
Number Field ◽  
Upper Bound ◽  
Class Group ◽  
Number Fields ◽  
Ideal Class ◽  
Ideal Class Group ◽  
Class Groups ◽  
Ring Of Integers

AbstractAn upper bound is given for the order of the kernel of the map on Sideal class groups that is induced by For some special types of number fields F the connection between the size of the above kernel for and the units and norms in are examined. Let K2(O) denote the Milnor K-group of the ring of integers of a number field. In some cases a formula by Conner, Hurrelbrink and Kolster is extended to show how closely the 4-rank of is related to the 4-rank of the S-ideal class group of

An arithmetic characterization of algebraic number fields with a given class group

1983 ◽  
Vol 94 (1) ◽  
pp. 23-28 ◽  
Author(s):  
David E. Rush
Keyword(s):  
Abelian Group ◽  
Algebraic Number ◽  
Class Group ◽  
Finite Abelian Group ◽  
Number Fields ◽  
Unique Factorization ◽  
Class Groups ◽  
Algebraic Number Fields ◽  
Ring Of Integers

Let R be the ring of integers of a number field K with class group G. It is classical that R is a unique factorization domain if and only if G is the trivial group; and the finite abelian group G is generally considered as a measure of the failure of unique factorization in R. The first arithmetic description of rings of integers with non-trivial class groups was given in 1960 by L. Carlitz (1). He proved that G is a group of order ≤ two if and only if any two factorizations of an element of R into irreducible elements have the same number of factors. In ((6), p. 469, problem 32) W. Narkiewicz asked for an arithmetic characterization of algebraic number fields K with class numbers ≠ 1, 2. This problem was solved for certain class groups with orders ≤ 9 in (2), and for the case that G is cyclic or a product of k copies of a group of prime order in (5). In this note we solve Narkiewicz's problem in general by giving arithmetical characterizations of a ring of integers whose class group G is any given finite abelian group.

scholarly journals ON THE MERTENS–CESÀRO THEOREM FOR NUMBER FIELDS

2015 ◽  
Vol 93 (2) ◽  
pp. 199-210 ◽  
Author(s):  
ANDREA FERRAGUTI ◽  
GIACOMO MICHELI
Keyword(s):  
Zeta Function ◽  
Number Field ◽  
Number Fields ◽  
Algebraic Integers ◽  
Ring Of Integers ◽  
Dedekind Zeta Function ◽  
Natural Density ◽  
Suitable Notion

Let $K$ be a number field with ring of integers ${\mathcal{O}}$. After introducing a suitable notion of density for subsets of ${\mathcal{O}}$, generalising the natural density for subsets of $\mathbb{Z}$, we show that the density of the set of coprime $m$-tuples of algebraic integers is $1/{\it\zeta}_{K}(m)$, where ${\it\zeta}_{K}$ is the Dedekind zeta function of $K$. This generalises a result found independently by Mertens [‘Ueber einige asymptotische Gesetze der Zahlentheorie’, J. reine angew. Math. 77 (1874), 289–338] and Cesàro [‘Question 75 (solution)’, Mathesis 3 (1883), 224–225] concerning the density of coprime pairs of integers in $\mathbb{Z}$.

GAUSS AND KLOOSTERMAN SUMS OVER RESIDUE RINGS OF ALGEBRAIC INTEGERS

2011 ◽  
Vol 07 (01) ◽  
pp. 101-114
Author(s):  
S. GURAK
Keyword(s):  
Classical Result ◽  
Classical Case ◽  
Rational Numbers ◽  
Kloosterman Sums ◽  
Gauss Sum ◽  
Algebraic Integers ◽  
Ring Of Integers ◽  
Rings Of Algebraic Integers ◽  
Sum Formula ◽  
Recent Evaluation

Let K be a field of degree n over Q, the field of rational numbers, with ring of integers O. Fix an integer m > 1, say with [Formula: see text] as a product of distinct prime powers, and let χ be a numerical character modulo m of conductor f(χ). Set ζm = exp (2πi/m) and let M be any ideal of O satisfying Tr M ⊆ mZ and N(1 + M) ⊆ 1 + f(χ)Z, where Tr and N are the trace and norm maps for K/Q. Then the Gauss sum [Formula: see text] is well-defined. If in addition N(1 + M) ⊆ 1 + mZ, then the Kloosterman sums [Formula: see text] are well-defined for any numerical character η ( mod m). The computation of GM(χ) and RM(η, z) is shown to reduce to their determination for m = pr, a power of a prime p, where M is comprised solely of ideals of K lying above p. In this setting we first explicitly determine GM(χ) for m = pr (r > 1) generalizing Mauclaire's classical result for K = Q. Relying on the recent evaluation of Kloosterman sums for prime powers in p-adic fields, we then proceed to compute the Kloosterman sums RM(η, z) here for m = pr (r > 1) when o(η) | p -1. This determination generalizes Salie's result in the classical case K = Q with o(η) = 1 or 2.

Existential definability with bounds on archimedean valuations

2003 ◽  
Vol 68 (3) ◽  
pp. 860-878 ◽  
Author(s):  
Alexandra Shlapentokh
Keyword(s):  
Real Number ◽  
Number Fields ◽  
Algebraic Integers ◽  
Hilbert's Tenth Problem ◽  
Hilbert’S Tenth Problem ◽  
Rings Of Algebraic Integers

AbstractWe show that a solution to Hilbert's Tenth Problem in the rings of algebraic integers and bigger subrings of number fields where it is currently not known, is equivalent to a problem of bounding archimedean valuations over non-real number fields.

Comparison of K-Theory Galois Module Structure Invariants

2000 ◽  
Vol 52 (1) ◽  
pp. 47-91 ◽  
Author(s):  
T. Chinburg ◽  
M. Kolster ◽  
V. P. Snaith
Keyword(s):  
Class Group ◽  
Module Structure ◽  
Galois Module ◽  
Comparison Result ◽  
Algebraic Integers ◽  
Galois Module Structure ◽  
Rings Of Algebraic Integers ◽  
K Theory

AbstractWe prove that two, apparently different, class-group valued Galoismodule structure invariants associated to the algebraic K-groups of rings of algebraic integers coincide. This comparison result is particularly important in making explicit calculations.

The 2-Sylow-Subgroup of the Tame Kernel of Number Fields

1991 ◽  
Vol 43 (2) ◽  
pp. 255-264 ◽  
Author(s):  
Boris Brauckmann
Keyword(s):  
Number Field ◽  
Sylow Subgroup ◽  
Class Group ◽  
Quadratic Extension ◽  
Number Fields ◽  
Surjective Homomorphism ◽  
Ring Of Integers ◽  
Tame Kernel

For a number field F with ring of integers OF the tame symbols yield a surjective homomorphism with a finite kernel, which is called the tame kernel, isomorphic to K2(OF). For the relative quadratic extension E/F, where and E ≠ F, let CS(E/ F)(2) denote the 2-Sylow-subgroup of the relative S-class-group of E over F, where S consists of all infinite and dyadic primes of F, and let m be the number of dyadic primes of F, which decompose in E.

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