On sectional paths in a category of complexes of fixed size

We show how to build the Auslander-Reiten quiver of the category Cn(proj A)of complexes of size n ≥ 2, for any artin algebra A. We also give conditions over the complexes in Cn(proj A) under which the composition of irreducible morphisms in sectional paths vanishes.Fil: Chaio, Claudia Alicia. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Pratti, Nilda Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Souto-Salorio, M. José. Universidad de Coruña; Españ

El esfuerzo por pensar distinto: ensayo sobre el afuera y el alejamiento deuno mismo en la obra de Michel Foucault

[Resumen]: La obra de Michel Foucault, en primer lugar, nos acerca el conocimiento de un poder cuyo origen es idéntico al del ser humano que surge del siglo XVIII. A partir de ese origen, el cuerpo, la biografía y el deseo se convierten en espacios privilegiados para así lograr un óptimo establecimiento de las técnicas disciplinarias. En último momento, Foucault invita a trabajar un pensamiento nuevo, más vigente, donde las nociones de poder y libertad tenderían a formar parte de una misma línea. Se propone como objeto de este estudio enfrentar justo el cambio de perspectiva en el pensamiento foucaultiano, que provoca que las disciplinas se ubiquen ahora dentro de un contexto amplio, complejo y en el que no todo es previsible. El interés de Foucault gira hacia un tipo de poder que principalmente hace funcionar la libertad para luego gestionarla[Abstract:] Firstly, the work by Michel Foucault brings us the knowledge of a power whose source is identical to the human being who arises from 18th century. Since this origin the body, the biography and desire have become privileged spaces in order to obtain an optimal establishment of disciplinary techniques. At the last moment, Foucault encourages to work out a more effective new thinking, where the notions of power and freedom would tend to be part of the same line. The paper aims to examine the shift of perspective of Foucault’s thought, which places disciplines within a broader and more complex framework, in which not everything can be foreseen. In regard to this, Foucault’s research interests begin to focus on a type of power which is primarily aimed at organising freedom, so as to subsequently managing it

Irreducible morphisms in the bounded derived category

AbstractWe study irreducible morphisms in the bounded derived category of finitely generated modules over an Artin algebra Λ, denoted Db(Λmod), by means of the underlying category of complexes showing that, in fact, we can restrict to the study of certain subcategories of finite complexes. We prove that as in the case of modules there are no irreducible morphisms from X to X if X is an indecomposable complex. In case Λ is a selfinjective Artin algebra we show that for every irreducible morphism f in Cb(Λproj) either fj is split monomorphism for all j∈Z or split epimorphism, for all j∈Z. Moreover, we prove that all the non-trivial components of the Auslander–Reiten quiver of Cb(Λproj) are of the form ZA∞

Graphs with isolation number equal to one third of the order

A set $D$ of vertices of a graph $G$ is isolating if the set of vertices not in $D$ or with no neighbor in $D$ is independent. The isolation number of $G$, denoted by $\iota (G)$, is the minimum cardinality of an isolating set of $G$. It is known that $\iota (G)\le n/3$, if $G$ is a connected graph of order $n$, $n\ge 3$, distinct from $C_5$. The main result of this work is the characterisation of unicyclic and block graphs of order $n$ with isolating number equal to $n/3$. Moreover, we provide a family of general graphs attaining this upper bound on the isolation number.Comment: 15 pages, 12 figure

Quality ratings of frequency-compressed speech by participants with extensive high-frequency dead regions in the cochlea.

OBJECTIVE: The objective was to assess the degradation of speech sound quality produced by frequency compression for listeners with extensive high-frequency dead regions (DRs). DESIGN: Quality ratings were obtained using values of the starting frequency (Sf) of the frequency compression both below and above the estimated edge frequency, fe, of each DR. Thus, the value of Sf often fell below the lowest value currently used in clinical practice. Several compression ratios were used for each value of Sf. Stimuli were sentences processed via a prototype hearing aid based on Phonak Exélia Art P. STUDY SAMPLE: Five participants (eight ears) with extensive high-frequency DRs were tested. RESULTS: Reductions of sound-quality produced by frequency compression were small to moderate. Ratings decreased significantly with decreasing Sf and increasing CR. The mean ratings were lowest for the lowest Sf and highest CR. Ratings varied across participants, with one participant rating frequency compression lower than no frequency compression even when Sf was above fe. CONCLUSIONS: Frequency compression degraded sound quality somewhat for this small group of participants with extensive high-frequency DRs. The degradation was greater for lower values of Sf relative to fe, and for greater values of CR. Results varied across participants.Action on Hearing Loss, Phonak AG, H.B. Allen Trust, Medical Research CouncilThis is the final version of the article. It first appeared from Taylor & Francis via http://dx.doi.org/10.1080/14992027.2016.123407

As dificultades de incorporación das mulleres matemáticas á universidade

[RESUMO] Votamos una ollada as primeiras mulleres matemáticas no eido universitario en Europa dende finais do século XIX, analizamos tamén a situación actual en datos porcentuais facendo especial fincapé nas mulleres españolas e nas galegas. Destacamos as singularidades dalgunhas mulleres que nun ámbito desfavorable sobresaíron polos seus logros académicos e/ou científicos

On the Degree in Categories of Complexes of Fixed Size

This version of the article has been accepted for publication, after peer review and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s10485-019-09557-x.[Abstract]: We consider Λ an artin algebra and n ≥ 2. We study how to compute the left and right degrees of irreducible morphisms between complexes in a generalized standard Auslander-Reiten component of Cn(proj Λ) with length. We give conditions under which the kernel and the cokernel of irreducible morphisms between complexes in Cn(proj Λ) belong to such a category. For a finite dimensional hereditary algebra H over an algebraically closed field, we determine when an irreducible morphism has finite left (or right) degree and we give a characterization, depending on the degrees of certain irreducible morphisms, under which Cn(proj H) is of finite type.The first and second authors thankfully acknowledge partial support from CONICET and EXA558/14 from Universidad Nacional de Mar del Plata, Argentina. The third author thankfully acknowledge support from Ministerio Español de Economía y Competitividad and FEDER (FFI2014-51978-C2-2-R). The first author is a researcher from CONICET.Argentina. Universidad Nacional de Mar del Plata; EXA558/14Cn(proj Λ) H n ≥ 2

Influencia del software de geometría dinámica en la visualización matemática

Este trabajo tiene como objetivo exponer los aspectos teóricos relativos a la influencia del software de Geometría dinámica en el desarrollo de la visualización matemática con base a los resultados de las principales investigaciones realizadas en este ámbito. Se describe el marco teórico en el que encuadramos la presente investigación, y en particular se define el término visualización y se expone su importancia en el aprendizaje de la Geometría. Asimismo, se enuncian las dificultades que se encuentran en la práctica de la visualización y se explican las distintas pruebas existentes para evaluar la visualización. En último lugar, se detallan los beneficios del uso del software de Geometría dinámica para el desarrollo de la visualización