135,593 research outputs found
Recursive Betti numbers for Cohen-Macaulay d-partite clutters arising from posets
No full textA natural extension of bipartite graphs are d-partite clutters, where d >= 2 is an integer. For a poset P, Ene, Herzog and Mohammadi introduced the d-partite clutter C_{P,d} of multichains of length d in P, showing that it is Cohen-Macaulay. We prove that the cover ideal of C_{P,d} admits an x(i)-splitting, determining a recursive formula for its Betti numbers and generalizing a result of Francisco, Ha and Van Tuyl on the cover ideal of Cohen-Macaulay bipartite graphs. Moreover we prove a Betti splitting result for the Alexander dual of a Cohen Macaulay simplicial complex. Interesting examples are given, in particular the first example of ideal that does not admit Betti splitting in any characteristic
The Image of Precarious Employment in Statistical Sources: the Italian Case
No full textThe precariousness of labour is a characteristic of the labour market that is becoming increasingly widespread in the more highly developed capitalist societies. (e chapter studies how this phenomenon has been represented in Italian statistical sources in the last thirty years. The aim is to reconstruct a picture of the precariousness of work as it emerges from this particular type of source. For this reason we will be specifying the type of quantitative and qualitative analysis of the phenomenon, the criteria of classification and the terminology. These are all elements that together constitute the language of the sources examined and thus represent the medium and mode of presentation of the phenomenon in these sources. Italy in the last thirty years is referred to because here, as in other industrially very advanced countries, the phenomenon of precarious work contracts has reached increasingly significant levels. The historical point of view adopted in the chapter enables us to make three clear points. First, the precariousness of labour as studied is not a new occurrence in the history of industrial capitalism. Second, the reasons why this phenomenon has reached an unprecedented level in more recent times have been examined. Third, historical analysis is particularly useful in the critical examination of statistical sources, both in order to question how far they can be trusted to reflect the true extent of the phenomenon and in order to reconstruct the kind of representation they afford of job precariousness.
Gender specifics are also considered and a comparison is made between the trend in Italy and that in other European countries
Betti numbers of configuration spaces of surfaces
No full textWe give explicit formulas for the Betti numbers, both stable and unstable, of the unordered
configuration spaces of an arbitrary surface of finite type. (C) 2017 London Mathematical Society111Nsciescopu
Orazione fvnerale di Benedetto Betti : da lui publicamente recitata nelle esequie del sereniss. Cosimo Medici gran duca di Toscana : celebrate il dì 13. de giugnio 1574. nella Compagnia di S. Giouanni Vangelista : con la descrizione dell'apparato messa nel fine.
No full textWoodcuts: small portrait of Cosimo I on C4 verso, armorial title-vignette, historiated initials, printer's devise on D3 verso."Ordine dell'apparato fatto da' giovani della Compagnia di San Gio. Vangelista nell'esequie del serenissimo gran duca, celebrate nel loro oratorio, raccolto da Antonio Padouani"--D1-D3.The last leaf is blank.Signatures: A-D⁴.Mode of access: Internet
Non-orientable surface-plus-one-relation groups
No full textRecently Dicks–Linnell determined the L2-Betti numbers of the orientable surface-plus-one-relation groups, and their arguments involved some results that were obtained topologically by Hempel and Howie. Using algebraic arguments, we now extend all these results of Hempel and Howie to a larger class of two-relator groups, and we then apply the extended results to determine the L2-Betti numbers of the non-orientable surface-plus-one-relation group
Betti numbers of multigraded modules
No full textAbstractIn this paper we deal with lower bounds for the Betti numbers of multigaded modules over R = k[x1,…, xd]. In general the ith Betti number of a finite length multigraded module must be at least the binomial coefficient (di). This is achieved only when the module in question is isomorphic to R modulo a maximal R-sequence. Otherwise the lower bound for each i is increased either by (d−1i) or by (d−1i−1). If M is an arbitrary multigraded module and s is the length of a maximal R sequence in the annihilator of M then similar inequalities hold for the Betti numbers of M with d replaced by d−s
Betti bounds of polynomials
No full textWe initiate a classification of polynomials f : Cn - C of degree d having the top Betti number of the general fibre close to the maximum. We find a range in which the polynomial must have isolated singularities and another range where it may have at most one line singularity of Morse transversal type. Our method uses deformations into particular pencils with non-isolated singularitie
Maximum Betti numbers of Čech complexes
No full textThe Upper Bound Theorem for convex polytopes implies that the p-th Betti number of the Čech complex of any set of N points in ℝ^d and any radius satisfies β_p = O(N^m), with m = min{p+1, ⌈d/2⌉}. We construct sets in even and odd dimensions, which prove that this upper bound is asymptotically tight. For example, we describe a set of N = 2(n+1) points in ℝ³ and two radii such that the first Betti number of the Čech complex at one radius is (n+1)² - 1, and the second Betti number of the Čech complex at the other radius is n²
LA LENGUA ESPAÑOLA Y LO HISPANO EN LOS ESTADOS UNIDOS
No full text"Este nuevo libro propone un acercamiento al español en contacto con el inglés en los Estados Unidos y lo hace en un tono ameno, impregnado de empatía para su objeto de estudio, pero abordándolo a la vez con el rigor y la profundidad que se merece. Se trata, pues, de una lectura imprescindible para las bibliotecas de todos los investigadores del español, esta segunda lengua de los Estados Unidos, todavía poco entendida y poco apreciada en toda su complejidad. Una lectura que recomiendo encarecidamente” D. Dumitresc
OSSERVAZIONI SULL'USO E DURATA DELLE RESINE COMPOSITE NEL TRATTAMENTO DELLE LESIONI CORONALI DENTALI: RIFLESSI SUL RISARCIMENTO DEL DANNO DENTARIO
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