168,915 research outputs found

    Monochromatic Clique Decompositions of Graphs

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    Let GG be a graph whose edges are coloured with kk colours, and H=(H1,,Hk)\mathcal H=(H_1,\dots , H_k) be a kk-tuple of graphs. A monochromatic H\mathcal H-decomposition of GG is a partition of the edge set of GG such that each part is either a single edge or forms a monochromatic copy of HiH_i in colour ii, for some 1ik1\le i\le k. Let ϕk(n,H)\phi_{k}(n,\mathcal H) be the smallest number ϕ\phi, such that, for every order-nn graph and every kk-edge-colouring, there is a monochromatic H\mathcal H-decomposition with at most ϕ\phi elements. Extending the previous results of Liu and Sousa ["Monochromatic KrK_r-decompositions of graphs", Journal of Graph Theory}, 76:89--100, 2014], we solve this problem when each graph in H\mathcal H is a clique and nn0(H)n\ge n_0(\mathcal H) is sufficiently large.Comment: 14 pages; to appear in J Graph Theor

    Asset Returns Under Model Uncertainty: Eveidence from the euro area, the U.K and the U.S

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    The goal of thes paper is to analyze predictability of future asset returns in the context of model uncertainty. Using data for the euro area, the US and the U.K., we show that one can improve the forecasts of stock returns using a Bayesian Model Averaging (BMA) approach, and there is a large amount of model uncertainty. The empirical evidence for the euro area suggests that several macroeconomic, financial and macro-financial variables are consistently among the most prominent determinants of risk premium. As for the U.S, only a few number of predictors play an important role. In the case of the UK, future stock returns are better forecasted by financial variables. These results are corroborated for both the M-open and the M-closed perspectives and in the context of "in-sample" and "out-of-sample" forescating. Finally, we highlight that the predictive ability of the BMA framework is stronger at longer periods, and clearly outperforms the constant expected returns and the autoregressive benchmark models.stock returns, model uncertainty, Bayesian Model Averaging

    Sex and recombination in the H\"otzel aging model

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    Why sex evolved and it prevails in nature remains one of the great puzzles of evolution. Most biologists would explain that it promotes genetic variability, however this explanation suffers from several difficulties. What advantages might sex confer? The present communication aims at certain investigations related to this question, in this way we introduce sexual recombination on the H\"otzel model (with males and females) and we compare these results with those from asexual reproduction without recombination.Comment: 10 pages, 6 figure