scholarly journals Exploring the Beginnings of Algebraic K-Theory

2021 ◽  
Author(s):  
Sarah Schott
Keyword(s):  
Abelian Group ◽  
Linear Algebra ◽  
Polynomial Ring ◽  
Division Ring ◽  
Free Abelian Group ◽  
Linear Analysis ◽  
Finitely Generated ◽  
Ideal Domain ◽  
K Theory

According to Atiyah, K-theory is that part of linear algebra that studies additive or abelian properties (e.g. the determinant). Because linear algebra, and its extensions to linear analysis, is ubiquitous in mathematics, K-theory has turned out to be useful and relevant in most branches of mathematics. Let R be a ring. One defines K0(R) as the free abelian group whose basis are the finitely generated projective R-modules with the added relation P ⊕ Q = P + Q. The purpose of this thesis is to study simple settings of the K-theory for rings and to provide a sequence of examples of rings where the associated K-groups K0(R) get progressively more complicated. We start with R being a field or a principle ideal domain and end with R being a polynomial ring on two variables over a non-commutative division ring.

Dehn functions of finitely presented metabelian groups

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wenhao Wang
Keyword(s):  
Abelian Group ◽  
Upper Bound ◽  
Finite Rank ◽  
Free Abelian Group ◽  
Metabelian Group ◽  
Finitely Generated ◽  
Dehn Function ◽  
Metabelian Groups ◽  
Dehn Functions ◽  
Finitely Presented

Abstract In this paper, we compute an upper bound for the Dehn function of a finitely presented metabelian group. In addition, we prove that the same upper bound works for the relative Dehn function of a finitely generated metabelian group. We also show that every wreath product of a free abelian group of finite rank with a finitely generated abelian group can be embedded into a metabelian group with exponential Dehn function.

scholarly journals On the automorphisms of the group ring of a finitely generated free abelian group

1988 ◽  
Vol 31 (1) ◽  
pp. 71-75
Author(s):  
M. M. Parmenter
Keyword(s):  
Abelian Group ◽  
Prime Ideal ◽  
Group Ring ◽  
Associative Ring ◽  
Free Abelian Group ◽  
Finitely Generated ◽  
Torsion Free Abelian Group ◽  
Special Case ◽  
Torsion Free

Let R be an associative ring with 1 and G a finitely generated torsion-free abelian group. In this note, we classify all R-automorphisms of the group ring RG. The special case where G is infinite cyclic was previously settled in [8], and our interest in this problem was rekindled by the recent paper of Mehrvarz and Wallace [7], who carried out the classification in the case where R contains a nilpotent prime ideal.

scholarly journals A NOTE ON NIELSEN EQUIVALENCE IN FINITELY GENERATED ABELIAN GROUPS

2011 ◽  
Vol 84 (1) ◽  
pp. 127-136 ◽  
Author(s):  
DANIEL OANCEA
Keyword(s):  
Abelian Group ◽  
Equivalence Class ◽  
Free Group ◽  
Free Abelian Group ◽  
Abelian Groups ◽  
Finitely Generated ◽  
Finite Abelian Groups ◽  
Arbitrary Rank ◽  
Generating Sets

AbstractNielsen transformations determine the automorphisms of a free group of rank n, and also of a free abelian group of rank n, and furthermore the generating n-tuples of such groups form a single Nielsen equivalence class. For an arbitrary rank n group, the generating n-tuples may fall into several Nielsen classes. Diaconis and Graham [‘The graph of generating sets of an abelian group’, Colloq. Math.80 (1999), 31–38] determined the Nielsen classes for finite abelian groups. We extend their result to the case of infinite abelian groups.

scholarly journals Note on Automorphisms of a Free Abelian Group

1980 ◽  
Vol 23 (1) ◽  
pp. 111-113 ◽  
Author(s):  
Olga Macedońska-Nosalska
Keyword(s):  
Abelian Group ◽  
Free Group ◽  
Quotient Group ◽  
Commutator Subgroup ◽  
Free Abelian Group ◽  
Finitely Generated

Let F be a free group. Denote by the quotient group by the commutator subgroup which is a free abelian group. The fact that the natural map from Aut(F) into Aut() is an epimorphism, in case when F is finitely generated, was known as a consequence of the theory of Nielsen transformations ([2]) Proposition 4.4 and [3] Corollary 3.5.1).

scholarly journals ABELIAN GROUPS WITH A p2-BOUNDED SUBGROUP, REVISITED

2011 ◽  
Vol 10 (03) ◽  
pp. 377-389
Author(s):  
CARLA PETRORO ◽  
MARKUS SCHMIDMEIER
Keyword(s):  
Abelian Group ◽  
Prime Number ◽  
Maximal Ideal ◽  
Abelian Groups ◽  
Finitely Generated ◽  
Uniserial Ring

Let Λ be a commutative local uniserial ring of length n, p be a generator of the maximal ideal, and k be the radical factor field. The pairs (B, A) where B is a finitely generated Λ-module and A ⊆B a submodule of B such that pmA = 0 form the objects in the category [Formula: see text]. We show that in case m = 2 the categories [Formula: see text] are in fact quite similar to each other: If also Δ is a commutative local uniserial ring of length n and with radical factor field k, then the categories [Formula: see text] and [Formula: see text] are equivalent for certain nilpotent categorical ideals [Formula: see text] and [Formula: see text]. As an application, we recover the known classification of all pairs (B, A) where B is a finitely generated abelian group and A ⊆ B a subgroup of B which is p2-bounded for a given prime number p.

On Commutator Length and Square Length of the Wreath Product of a Group by a Finitely Generated Abelian Group

2010 ◽  
Vol 17 (spec01) ◽  
pp. 799-802 ◽  
Author(s):  
Mehri Akhavan-Malayeri
Keyword(s):  
Abelian Group ◽  
Wreath Product ◽  
Finitely Generated ◽  
Commutator Length

Let W = G ≀ H be the wreath product of G by an n-generator abelian group H. We prove that every element of W′ is a product of at most n+2 commutators, and every element of W2 is a product of at most 3n+4 squares in W. This generalizes our previous result.

scholarly journals RATIONAL POLYHEDRA AND PROJECTIVE LATTICE-ORDERED ABELIAN GROUPS WITH ORDER UNIT

2012 ◽  
Vol 14 (03) ◽  
pp. 1250017 ◽  
Author(s):  
LEONARDO CABRER ◽  
DANIELE MUNDICI
Keyword(s):  
Abelian Group ◽  
Algebraic Topology ◽  
Lattice Structure ◽  
Order Unit ◽  
Finitely Generated ◽  
Lattice Order ◽  
Translation Invariant ◽  
Projective Lattice ◽  
Rational Polyhedra ◽  
Finitely Presented

An ℓ-groupG is an abelian group equipped with a translation invariant lattice-order. Baker and Beynon proved that G is finitely generated projective if and only if it is finitely presented. A unital ℓ-group is an ℓ-group G with a distinguished order unit, i.e. an element 0 ≤ u ∈ G whose positive integer multiples eventually dominate every element of G. Unital ℓ-homomorphisms between unital ℓ-groups are group homomorphisms that also preserve the order unit and the lattice structure. A unital ℓ-group (G, u) is projective if whenever ψ : (A, a) → (B, b) is a surjective unital ℓ-homomorphism and ϕ : (G, u) → (B, b) is a unital ℓ-homomorphism, there is a unital ℓ-homomorphism θ : (G, u) → (A, a) such that ϕ = ψ ◦ θ. While every finitely generated projective unital ℓ-group is finitely presented, the converse does not hold in general. Classical algebraic topology (à la Whitehead) is combined in this paper with the Włodarczyk–Morelli solution of the weak Oda conjecture for toric varieties, to describe finitely generated projective unital ℓ-groups.

On the SL(2, C)-representation rings of free abelian groups

2018 ◽  
Vol 167 (02) ◽  
pp. 229-247
Author(s):  
TAKAO SATOH
Keyword(s):  
Abelian Group ◽  
Upper Bound ◽  
Automorphism Groups ◽  
Free Abelian Group ◽  
Abelian Groups ◽  
Free Groups ◽  
The Other ◽  
Subsequent Research ◽  
Representation Rings ◽  
Free Abelian Groups

AbstractIn this paper, we study “the ring of component functions” of SL(2, C)-representations of free abelian groups. This is a subsequent research of our previous work [11] for free groups. We introduce some descending filtration of the ring, and determine the structure of its graded quotients.Then we give two applications. In [30], we constructed the generalized Johnson homomorphisms. We give an upper bound on their images with the graded quotients. The other application is to construct a certain crossed homomorphisms of the automorphism groups of free groups. We show that our crossed homomorphism induces Morita's 1-cocycle defined in [22]. In other words, we give another construction of Morita's 1-cocyle with the SL(2, C)-representations of the free abelian group.

Sign in / Sign up

Export Citation Format

Share Document