scholarly journals A distributive semilattice not isomorphic to the maximal semilattice quotient of the positive cone of any dimension group

2003 ◽  
Vol 268 (1) ◽  
pp. 290-300 ◽  
Author(s):  
Pavel Růžička
1989 ◽  
Vol 04 (20) ◽  
pp. 1883-1890 ◽  
Author(s):  
DAVID E. EVANS ◽  
JEREMY D. GOULD

If Γ is a graph, with distinguished vertex *, let A(Γ) denote the non-commutative path algebra on the space [Formula: see text] of semi-infinite paths in Γ beginning at *. Embeddings A(Γ1)→A(Γ2) of non-commutative AF algebras associated with graphs Γ1 and Γ2 are discussed from a dimension group point of view. For certain infinite T-shaped graphs, we have K0(A(Γ))≃ ℤ[t], with positive cone identified with {0}∪{P∈ℤ(t): P(λ)>0, λ∈(0,γ]}, where γ=γ(Γ)= ||Γ||−2<1/4. Hence for certain graphs there exists a unital homomorphism A(Γ1)→A(Γ2) if ||Γ1||=||Γ2||. For certain finite T-shaped graphs K0(A(Γ))≃ℤ[t]/<Q> where <Q> denotes the ideal generated by a polynomial Q=Q(Γ) which is essentially the characteristic polynomial of the graph Γ, and positive cone identified with {0}∪{f+<Q>: f(γ)>0} where γ=γ(Γ)=||Γ||−2. Hence there exists a unital homomorphism A(Γ1)→A(Γ2) if ||Γ1||=||Γ2||, and Q(Γ1) divides Q(Γ2). The structure of K0(A(Γ)) as an ordered ring is related to the fusion rules of rational conformal field theory. Moreover, for these T-shaped graphs there is an algebraic presentation which further illuminates the above embeddings. This presentation involves a new projection and a new relation in addition to those of Temperley-Lieb, and gives a rigidity above index four.


1994 ◽  
Vol 05 (03) ◽  
pp. 291-327 ◽  
Author(s):  
DAVID E. EVANS ◽  
JEREMY D. GOULD

If Γ is a graph, with distinguished vertex *, let A(Γ) denote the non-commutative path algebra on the space [Formula: see text] of semi-infinite paths in Γ beginning at *. We discuss embeddings A(Γ1) → A(Γ2) of AF algebras associated with graphs Γ1 and Γ2 from a dimension group point of view. For certain infinite T-shaped graphs, we have K0(A(Γ)) ≅ ℤ [t], with positive cone identified with {0}∪ {P ∈ ℤ [t]: P (λ) > 0, λ ∈ (0, γ]}, where γ = γ (Γ) =||Γ||−2 < 1/4. Hence for certain graphs there exists a unital homomorphism A(Γ1) → A(Γ2) if ||Γ1|| ≤ ||Γ2||. For certain finite T-shaped graphs K0 (A(Γ)) ≅ ℤ [t]/<Q> where <Q> denotes the ideal generated by a polynomial Q=Q(Γ) which is essentially the characteristic polynomial of the graph Γ and positive cone identified with {0}∪ {f + <Q>: f(γ) > 0} where γ = γ(Γ) = ||Γ||-2. Hence there exists a unital homomorphism A(Γ1) → A(Γ2) if ||Γ1|| = ||Γ2||, and Q(Γ2) divides Q(Γ1). The structure of K0(A(Γ)) as an ordered ring is related to the fusion rules of rational conformal field theory.


2020 ◽  
Vol 18 (1) ◽  
pp. 858-872
Author(s):  
Imed Kedim ◽  
Maher Berzig ◽  
Ahdi Noomen Ajmi

Abstract Consider an ordered Banach space and f,g two self-operators defined on the interior of its positive cone. In this article, we prove that the equation f(X)=g(X) has a positive solution, whenever f is strictly \alpha -concave g-monotone or strictly (-\alpha ) -convex g-antitone with g super-homogeneous and surjective. As applications, we show the existence of positive definite solutions to new classes of nonlinear matrix equations.


2016 ◽  
Vol 26 (08) ◽  
pp. 1650135 ◽  
Author(s):  
C. A. Cardoso ◽  
J. A. Langa ◽  
R. Obaya

In this paper, we describe in detail the global and cocycle attractors related to nonautonomous scalar differential equations with diffusion. In particular, we investigate reaction–diffusion equations with almost-periodic coefficients. The associated semiflows are strongly monotone which allow us to give a full characterization of the cocycle attractor. We prove that, when the upper Lyapunov exponent associated to the linear part of the equations is positive, the flow is persistent in the positive cone, and we study the stability and the set of continuity points of the section of each minimal set in the global attractor for the skew product semiflow. We illustrate our result with some nontrivial examples showing the richness of the dynamics on this attractor, which in some situations shows internal chaotic dynamics in the Li–Yorke sense. We also include the sublinear and concave cases in order to go further in the characterization of the attractors, including, for instance, a nonautonomous version of the Chafee–Infante equation. In this last case we can show exponentially forward attraction to the cocycle (pullback) attractors in the positive cone of solutions.


2017 ◽  
Vol 27 (2) ◽  
pp. 357-363 ◽  
Author(s):  
Caio Augusto Hartman ◽  
Julio Cesar Teixeira ◽  
Sergio Bruno Barbosa ◽  
Stephanye Mariano Figueiredo ◽  
Liliana Aparecida Lucci De Angelo Andrade ◽  
...  

ObjectiveThe aim of this study was to evaluate the prognosis and recurrence of microinvasive squamous cervical (MIC) cancer stage IA1 in women treated conservatively or by hysterectomy, and followed-up to 20 years.MethodsIt was studied in a cohort of 139 women with MIC, 41 definitively managed by conization and 98 by hysterectomy from January 1994 to December 2003 and followed-up until 2013. The definitive treatment, age, conization technique (loop electrosurgical excision procedure or cold knife conization), cone margin, residual disease in hysterectomy specimen, and the association with recurrence (intraepithelial cervical neoplasia grade 3/intraepithelial vaginal neoplasia grade 3 or worse, and microinvasive or worse) were analyzed.ResultsThere were 2.5 times more conservative treatment in younger women than older (>40 years), and high proportion of residual disease in hysterectomy specimens (67% of intraepithelial cervical neoplasia grade 3 or worse), more common if positive cone margin (74% vs 35%, P < 0.002). There were 2.3% (3/133) recurrences detected as microinvasive or worse, and 6% (8/133) recurrences detected as intraepithelial cervical neoplasia grade 3/intraepithelial vaginal neoplasia grade 3 or worse: 7.3% (3/41) in the conization group and 5.4% (5/92) in the hysterectomy group (P = 0.701). Almost all recurrences (88%, 7/8) were diagnosed until 36 months after treatment, and they were not associated with conization technique. There were no differences in risk of recurrence and overall disease-free survival time related to type of treatment.ConclusionsThis study demonstrates the good prognosis of MIC, regardless the treatment. When fertility is not a concern, hysterectomy should be considered as definitive treatment to avoid the risk of residual disease. Regular follow-up for a long period should be maintained.


2000 ◽  
Vol 20 (2) ◽  
pp. 611-626 ◽  
Author(s):  
RICHARD SWANSON ◽  
HANS VOLKMER

Weak equivalence of primitive matrices is a known invariant arising naturally from the study of inverse limit spaces. Several new invariants for weak equivalence are described. It is proved that a positive dimension group isomorphism is a complete invariant for weak equivalence. For the transition matrices corresponding to periodic kneading sequences, the discriminant is proved to be an invariant when the characteristic polynomial is irreducible. The results have direct application to the topological classification of one-dimensional inverse limit spaces.


2018 ◽  
Vol 34 (3) ◽  
pp. 379-390
Author(s):  
HEMANT KUMAR NASHINE ◽  
◽  
HE YANG ◽  
RAVI P. AGARWAL ◽  
◽  
...  

In the present work, we discuss the existence of mild solutions for the initial value problem of fractional evolution equation of the form where C Dσ t denotes the Caputo fractional derivative of order σ ∈ (0, 1), −A : D(A) ⊂ X → X generates a positive C0-semigroup T(t)(t ≥ 0) of uniformly bounded linear operator in X, b > 0 is a constant, f is a given functions. For this, we use the concept of measure of noncompactness in partially ordered Banach spaces whose positive cone K is normal, and establish some basic fixed point results under the said concepts. In addition, we relaxed the conditions of boundedness, closedness and convexity of the set at the expense that the operator is monotone and bounded. We also supply some new coupled fixed point results via MNC. To justify the result, we prove an illustrative example that rational of the abstract results for fractional parabolic equations.


2017 ◽  
Vol 69 (3) ◽  
pp. 548-578 ◽  
Author(s):  
Michael Hartglass

AbstractWe study a canonical C* -algebra, 𝒮(Г,μ), that arises from a weighted graph (Г,μ), speci fic cases of which were previously studied in the context of planar algebras. We discuss necessary and sufficient conditions of the weighting that ensure simplicity and uniqueness of trace of 𝒮(Г,μ), and study the structure of its positive cone. We then study the *-algebra,𝒜, generated by the generators of 𝒮(Г,μ), and use a free differential calculus and techniques of Charlesworth and Shlyakhtenko as well as Mai, Speicher, and Weber to show that certain “loop” elements have no atoms in their spectral measure. After modifying techniques of Shlyakhtenko and Skoufranis to show that self adjoint elements x ∊ Mn(𝒜) have algebraic Cauchy transform, we explore some applications to eigenvalues of polynomials inWishart matrices and to diagrammatic elements in von Neumann algebras initially considered by Guionnet, Jones, and Shlyakhtenko.


2015 ◽  
Vol 36 (8) ◽  
pp. 2419-2440 ◽  
Author(s):  
MARÍA ISABEL CORTEZ ◽  
FABIEN DURAND ◽  
SAMUEL PETITE

We give conditions on the subgroups of the circle to be realized as the subgroups of eigenvalues of minimal Cantor systems belonging to a determined strong orbit equivalence class. Actually, the additive group of continuous eigenvalues $E(X,T)$ of the minimal Cantor system $(X,T)$ is a subgroup of the intersection $I(X,T)$ of all the images of the dimension group by its traces. We show, whenever the infinitesimal subgroup of the dimension group associated with $(X,T)$ is trivial, the quotient group $I(X,T)/E(X,T)$ is torsion free. We give examples with non-trivial infinitesimal subgroups where this property fails. We also provide some realization results.


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