scholarly journals Boundary quotients of the right Toeplitz algebra of the affine semigroup over the natural numbers

10.53733/90 ◽  
2021 ◽  
Vol 52 ◽  
pp. 109-143
Author(s):  
Astrid An Huef ◽  
Marcelo Laca ◽  
Iain Raeburn
Keyword(s):  
Regular Representation ◽  
Crossed Product ◽  
Ideal Structure ◽  
Toeplitz Algebra ◽  
Natural Numbers ◽  
Kms States ◽  
C Algebra ◽  
Affine Semigroup ◽  
Natural Dynamics ◽  
The Right

We study the Toeplitz $C^*$-algebra generated by the right-regular representation of the semigroup ${\mathbb N \rtimes \mathbb N^\times}$, which we call the right Toeplitz algebra. We analyse its structure by studying three distinguished quotients. We show that the multiplicative boundary quotient is isomorphic to a crossed product of the Toeplitz algebra of the additive rationals by an action of the multiplicative rationals, and study its ideal structure. The Crisp--Laca boundary quotient is isomorphic to the $C^*$-algebra of the group ${\mathbb Q_+^\times}\!\! \ltimes \mathbb Q$. There is a natural dynamics on the right Toeplitz algebra and all its KMS states factor through the additive boundary quotient. We describe the KMS simplex for inverse temperatures greater than one.

scholarly journals KMS STATES ON NICA–TOEPLITZ ALGEBRAS OF PRODUCT SYSTEMS

2012 ◽  
Vol 23 (12) ◽  
pp. 1250123 ◽  
Author(s):  
JEONG HEE HONG ◽  
NADIA S. LARSEN ◽  
WOJCIECH SZYMAŃSKI
Keyword(s):  
Finite Type ◽  
Lattice Ordered Group ◽  
Toeplitz Algebra ◽  
Product System ◽  
Natural Numbers ◽  
Ordered Group ◽  
Kms States ◽  
The Core ◽  
Product Systems ◽  
Affine Semigroup

We investigate KMS states of Fowler's Nica–Toeplitz algebra [Formula: see text] associated to a compactly aligned product system X over a semigroup P of Hilbert bimodules. This analysis relies on restrictions of these states to the core algebra which satisfy appropriate scaling conditions. The concept of product system of finite type is introduced. If (G, P) is a lattice ordered group and X is a product system of finite type over P satisfying certain coherence properties, we construct KMSβ states of [Formula: see text] associated to a scalar dynamics from traces on the coefficient algebra of the product system. Our results were motivated by, and generalize some of the results of Laca and Raeburn obtained for the Toeplitz algebra of the affine semigroup over the natural numbers.

scholarly journals Boundary quotients of the Toeplitz algebra of the affine semigroup over the natural numbers

2011 ◽  
Vol 32 (1) ◽  
pp. 35-62 ◽  
Author(s):  
NATHAN BROWNLOWE ◽  
ASTRID AN HUEF ◽  
MARCELO LACA ◽  
IAIN RAEBURN
Keyword(s):  
Uniqueness Theorem ◽  
Structure Theory ◽  
Recent Analysis ◽  
Crossed Products ◽  
Toeplitz Algebra ◽  
Natural Numbers ◽  
Kms States ◽  
Covariant Representations ◽  
Affine Semigroup

AbstractWe study the Toeplitz algebra 𝒯(ℕ⋊ℕ×) and three quotients of this algebra: the C*-algebra 𝒬ℕ recently introduced by Cuntz, and two new ones, which we call the additive and multiplicative boundary quotients. These quotients are universal for Nica-covariant representations of ℕ⋊ℕ× satisfying extra relations, and can be realised as partial crossed products. We use the structure theory for partial crossed products to prove a uniqueness theorem for the additive boundary quotient, and use the recent analysis of KMS states on 𝒯(ℕ⋊ℕ×) to describe the KMS states on the two quotients. We then show that 𝒯(ℕ⋊ℕ×), 𝒬ℕ and our new quotients are all interesting new examples for Larsen’s theory of Exel crossed products by semigroups.

scholarly journals KMS states on C*-algebras associated to local homeomorphisms

2014 ◽  
Vol 25 (08) ◽  
pp. 1450066 ◽  
Author(s):  
Zahra Afsar ◽  
Astrid an Huef ◽  
Iain Raeburn
Keyword(s):  
Finite Graph ◽  
Critical Value ◽  
Toeplitz Algebra ◽  
Graph Algebras ◽  
Kms States ◽  
C Algebra ◽  
C Algebras ◽  
Backward Shift ◽  
The One ◽  
Natural Dynamics

For every Hilbert bimodule over a C*-algebra, there are natural gauge actions of the circle on the associated Toeplitz algebra and Cuntz–Pimsner algebra, and hence natural dynamics obtained by lifting these gauge actions to actions of the real line. We study the KMS states of these dynamics for a family of bimodules associated to local homeomorphisms on compact spaces. For inverse temperatures larger than a certain critical value, we find a large simplex of KMS states on the Toeplitz algebra, and we show that all KMS states on the Cuntz–Pimsner algebra have inverse temperature at most this critical value. We illustrate our results by considering the backward shift on the one-sided path space of a finite graph, where we can use recent results about KMS states on graph algebras to see what happens below the critical value. Our results about KMS states on the Cuntz–Pimsner algebra of the shift show that recent constraints on the range of inverse temperatures obtained by Thomsen are sharp.

scholarly journals The primitive ideal space of the C*-algebra of the affine semigroup of algebraic integers

2012 ◽  
Vol 154 (1) ◽  
pp. 119-126 ◽  
Author(s):  
SIEGFRIED ECHTERHOFF ◽  
MARCELO LACA
Keyword(s):  
Recent Result ◽  
Orbit Space ◽  
Crossed Product ◽  
Primitive Ideal ◽  
Prime Ideals ◽  
Ideal Space ◽  
C Algebra ◽  
Ring Of Integers ◽  
Affine Semigroup ◽  
Power Set

AbstractThe purpose of this paper is to give a complete description of the primitive ideal space of the C*-algebra [R] associated to the ring of integers R in a number field K in the recent paper [5]. As explained in [5], [R] can be realized as the Toeplitz C*-algebra of the affine semigroup R ⋊ R× over R and as a full corner of a crossed product C0() ⋊ K ⋊ K*, where is a certain adelic space. Therefore Prim([R]) is homeomorphic to the primitive ideal space of this crossed product. Using a recent result of Sierakowski together with the fact that every quasi-orbit for the action of K ⋊ K* on contains at least one point with trivial stabilizer we show that Prim([R]) is homeomorphic to the quasi-orbit space for the action of K ⋊ K* on , which in turn may be identified with the power set of the set of prime ideals of R equipped with the power-cofinite topology.

scholarly journals Ideal structure of crossed products by endomorphisms via reversible extensions of C*-dynamical systems

2015 ◽  
Vol 26 (03) ◽  
pp. 1550022 ◽  
Author(s):  
Bartosz Kosma Kwaśniewski
Keyword(s):  
Dynamical System ◽  
Dynamical Systems ◽  
Transfer Operator ◽  
Crossed Product ◽  
Crossed Products ◽  
Ideal Structure ◽  
Gauge Invariant ◽  
C Algebra ◽  
System A ◽  
The Ideal

We consider an extendible endomorphism α of a C*-algebra A. We associate to it a canonical C*-dynamical system (B, β) that extends (A, α) and is "reversible" in the sense that the endomorphism β admits a unique regular transfer operator β⁎. The theory for (B, β) is analogous to the theory of classic crossed products by automorphisms, and the key idea is to describe the counterparts of classic notions for (B, β) in terms of the initial system (A, α). We apply this idea to study the ideal structure of a non-unital version of the crossed product C*(A, α, J) introduced recently by the author and A. V. Lebedev. This crossed product depends on the choice of an ideal J in (ker α)⊥, and if J = ( ker α)⊥ it is a modification of Stacey's crossed product that works well with non-injective α's. We provide descriptions of the lattices of ideals in C*(A, α, J) consisting of gauge-invariant ideals and ideals generated by their intersection with A. We investigate conditions under which these lattices coincide with the set of all ideals in C*(A, α, J). In particular, we obtain simplicity criteria that besides minimality of the action require either outerness of powers of α or pointwise quasinilpotence of α.

scholarly journals Phase transition on the Toeplitz algebra of the affine semigroup over the natural numbers

2010 ◽  
Vol 225 (2) ◽  
pp. 643-688 ◽  
Author(s):  
Marcelo Laca ◽  
Iain Raeburn
Keyword(s):  
Phase Transition ◽  
Toeplitz Algebra ◽  
Natural Numbers ◽  
Affine Semigroup

scholarly journals Type III1 equilibrium states of the Toeplitz algebra of the affine semigroup over the natural numbers

2011 ◽  
Vol 261 (1) ◽  
pp. 169-187 ◽  
Author(s):  
Marcelo Laca ◽  
Sergey Neshveyev
Keyword(s):  
Equilibrium States ◽  
Toeplitz Algebra ◽  
Natural Numbers ◽  
Type Iii1 ◽  
Affine Semigroup

scholarly journals The ideal structure of the Hecke $C^*$ -algebra of Bost and Connes

2000 ◽  
Vol 318 (3) ◽  
pp. 433-451 ◽  
Author(s):  
Marcelo Laca ◽  
Iain Raeburn
Keyword(s):  
Ideal Structure ◽  
C Algebra ◽  
The Ideal

scholarly journals Discrete product systems with twisted units

1995 ◽  
Vol 52 (2) ◽  
pp. 317-326 ◽  
Author(s):  
Marcelo Laca
Keyword(s):  
Dynamical System ◽  
Crossed Product ◽  
Type I ◽  
Crossed Products ◽  
Product System ◽  
C Algebra ◽  
Covariant Representations ◽  
Product Systems ◽  
Recent Theorem ◽  
I Factor

The spectral C*-algebra of the discrete product systems of H.T. Dinh is shown to be a twisted semigroup crossed product whenever the product system has a twisted unit. The covariant representations of the corresponding dynamical system are always faithful, implying the simplicity of these crossed products; an application of a recent theorem of G.J. Murphy gives their nuclearity. Furthermore, a semigroup of endomorphisms of B(H) having an intertwining projective semigroup of isometries can be extended to a group of automorphisms of a larger Type I factor.

scholarly journals Chief Series and Right Regular Representations of Finite p-Groups

1988 ◽  
Vol 44 (2) ◽  
pp. 225-232 ◽  
Author(s):  
Felix Leinen
Keyword(s):  
Regular Representation ◽  
Locally Finite ◽  
Regular Representations ◽  
Direct Limits ◽  
One To One ◽  
The Right

AbstractWe study the embeddings of a finite p-group U into Sylow p-subgroups of Sym (U) induced by the right regular representation p: U→ Sym(U). It turns out that there is a one-to-one correspondence between the chief series in U and the Sylow p-subgroups of Sym (U) containing Up. Here, the Sylow p-subgroup Pσ of Sym (U) correspoding to the chief series σ in U is characterized by the property that the intersections of Up with the terms of any chief series in Pσ form σp. Moreover, we see that p: U→ Pσ are precisely the kinds of embeddings used in a previous paper to construct the non-trivial countable algebraically closed locally finite p-groups as direct limits of finite p-groups.

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