1,721,815 research outputs found
Gibbula sirigui Brunetti M., Forli & Vecchi 2008
No full textGibbula sirigui Brunetti M., Forli & Vecchi, 2008 † Pleistocene (early Pleistocene): Mediterranean Sea (Italy) (Brunetti et al. 2008)Published as part of Harzhauser, Mathias, 2021, The Cainozoic to present-day record of Circum-Mediterranean, NE Atlantic and North Sea Cantharidinae and Trochinae (Trochoidea, Gastropoda) - a synopsis, pp. 1-81 in Zootaxa 4902 (1) on page 28, DOI: 10.11646/zootaxa.4902.1.1, http://zenodo.org/record/441908
Population ageing, household portfolios and financial asset returns: a survey of the literature
Full text linkPopulation ageing is a recognised phenomenon affecting many countries in the world including most EU ones, Japan and US. The financial implications of this phenomenon can be manifold and some recent literature has focused in particular on the possible consequences of ageing on household portfolios and on main financial asset returns ones. Overall, the extant literature on household portfolios reports a significant effect of age on asset allocation, thereby providing evidence in favour of the standard life-cycle hypothesis. On the other hand, empirical results on the link between demographics and financial asset prices/returns are less uniform. The aim of this paper is to systematize the extant literature on these issues and to provide an overview of the main results reported so far, trying to evaluate whether the different conclusions reached depend on the approach taken in the empirical exercises rather than on the actual differences, in terms of demographic dynamics, public pension systems and financial markets, of the realities considered
Eigenvalues of complex unit gain graphs and gain regularity
Full text linkA complex unit gain graph (or T -gain graph) Γ = (G, γ) is a gain graph with gains in T , the multiplicative
group of complex units. The T -outgain in Γ of a vertex v ∈ G is the sum of the gains of all the arcs
originating in v. A T -gain graph is said to be an a-T -regular graph if the T -outgain of each of its vertices is
equal to a. In this article, it is proved that a-T -regular graphs exist for every a ∈ R. This, in particular, means
that every real number can be a T -gain graph eigenvalue. Moreover, denoted by Ω(a) the class of connected
T-gain graphs whose largest eigenvalue is the real number a, it is shown that Ω(a) is nonempty if and only if a
belongs to {0} ∪ [1, +∞). In order to achieve these results, non-complete extended p-sums and suitably defined
joins of T -gain graphs are considered
A Lexicographic product for Signed Graphs
Full text linkA signed graph is a pair = (G; ), where G = (V (G);E(G)) is a graph
and E(G) {+1;−1} is the sign function on the edges of G. The
notion of composition (also known as lexicographic product) of two signed
graphs and = (H; ) already exists in literature, yet it fails to map
balanced graphs onto balanced graphs. We improve the existing denition
showing that our `new' signature on the lexicographic product of G and
H behaves well with respect to switching equivalence. Signed regularities
and some spectral properties are also discussed
Laplacian Spectral Properties of Signed Circular Caterpillars
Full text linkA circular caterpillar of girth n is a graph such that the removal of all pendant vertices yields a cycle Cn of order n. A signed graph is a pair Γ =(G,σ), where G is a simple graph and σ: E(G) →{+1, -1} is the sign function defined on the set E(G) of edges of G. The signed graph Γ is said to be balanced if the number of negatively signed edges in each cycle is even, and it is said to be unbalanced otherwise. We determine some bounds for the first n Laplacian eigenvalues of any signed circular caterpillar. As an application, we prove that each signed spiked triangle (G(3;p,q,r), σ), i.e. a signed circular caterpillar of girth 3 and degree sequence πp,q,r=(p+2,q+2,r+2,1,… 1), is determined by its Laplacian spectrum up to switching isomorphism. Moreover, in the set of signed spiked triangles of order N, we identify the extremal graphs with respect to the Laplacian spectral radius and the first two Zagreb indices. It turns out that the unbalanced spiked triangle with degree sequence πN-3,0,0 and the balanced spike triangle (G(3;\hat{p},\hat{q},\hat{r}),+), where each pair in {\hat{p}, \hat{q}, \hat{r} } differs at most by 1, respectively maximizes and minimizes the Laplacian spectral radius and both the Zagreb indices
The Put-Call Parity in the Index Options Markets. Further results for the Italian Mib30 Options market
Full text linkOrdering signed graphs with large index
Full text linkThe index of a signed graph is the largest eigenvalue of its adjacency matrix. We establish the first few signed graphs ordered decreasingly by the index in classes of connected signed graphs, connected unbalanced signed graphs and complete signed graphs with a fixed number of vertices
Economic Growth Rates and Recession Probabilities: the predictive power of the term spread in Italy
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