6,707 research outputs found

    La fonction de partition de Minc et une conjecture de Segal pour certains spectres de Thom

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    On construit dans cet article une résolution injective minimale dans la catégorie \U des modules instables sur l'algèbre de Steenrod modulo 22, de la cohomologie de certains spectres obtenus à partir de l'espace de Thom du fibré, associé à la représentation régulière réduite du groupe abélien élémentaire (Z/2)n(\Z/2)^n, au dessus de l'espace B(Z/2)nB(\Z/2)^n. Les termes de la résolution sont des produits tensoriels de modules de Brown-Gitler J(k)J(k) et de modules de Steinberg LnL_n introduits par S. Mitchell et S. Priddy. Ces modules sont injectifs d'après J. Lannes et S. Zarati, de plus ils sont indécomposables. L'existence de cette résolution avait été conjecturée par Jean Lannes et le deuxième auteur. La principale indication soutenant cette conjecture était un résultat combinatoire de G. Andrews : la somme alternée des séries de Poincaré des modules considérées est nulle

    Risk-Aware Energy Scheduling for Edge Computing with Microgrid: A Multi-Agent Deep Reinforcement Learning Approach

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    In recent years, multi-access edge computing (MEC) is a key enabler for handling the massive expansion of Internet of Things (IoT) applications and services. However, energy consumption of a MEC network depends on volatile tasks that induces risk for energy demand estimations. As an energy supplier, a microgrid can facilitate seamless energy supply. However, the risk associated with energy supply is also increased due to unpredictable energy generation from renewable and non-renewable sources. Especially, the risk of energy shortfall is involved with uncertainties in both energy consumption and generation. In this paper, we study a risk-aware energy scheduling problem for a microgrid-powered MEC network. First, we formulate an optimization problem considering the conditional value-at-risk (CVaR) measurement for both energy consumption and generation, where the objective is to minimize the expected residual of scheduled energy for the MEC networks and we show this problem is an NP-hard problem. Second, we analyze our formulated problem using a multi-agent stochastic game that ensures the joint policy Nash equilibrium, and show the convergence of the proposed model. Third, we derive the solution by applying a multi-agent deep reinforcement learning (MADRL)-based asynchronous advantage actor-critic (A3C) algorithm with shared neural networks. This method mitigates the curse of dimensionality of the state space and chooses the best policy among the agents for the proposed problem. Finally, the experimental results establish a significant performance gain by considering CVaR for high accuracy energy scheduling of the proposed model than both the single and random agent models.Comment: Accepted Article BY IEEE Transactions on Network and Service Management, DOI: 10.1109/TNSM.2021.304938

    Generalized free energy and thermodynamic phases of black holes in the gauged Kaluza-Klein theory

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    In the context of the generalized (off-shell) free energy, we explore the phase emergence and corresponding phase transitions of charged dilaton AdS\text{AdS} black holes in the gauged Kaluza-Klein (KK) theory where the KK vector field is gauged such that the fermionic fields are charged under the U(1)KK_{\text{KK}} gauge group. The black hole solutions are asymptotic to the AdSD_D geometry and can be realized as the dimensional reduction of the gauged supergravities on the compact internal manifolds, leading to the restriction as 4≤D≤74\leq D\leq 7. By studying the behavior of the generalized free energy under the change of the ensemble temperature, we determine the thermodynamic phases and the corresponding phase transitions of black holes. This is confirmed by investigating the heat capacity at the constant pressure and the on-shell free energy. In the canonical ensemble, the thermodynamics of black holes can be classified into three different classes as follows: (i) D=4D=4, (ii) D=5D=5, and (iii) D=6,7D=6,7. Whereas, in the grand canonical ensemble, the thermodynamics of black holes is independent of the number of spacetime dimensions and the pressure, but depends on the chemical potential Φ\Phi. The thermodynamic behavior of black holes can be classified into three different classes as follows: (i) Φ1\Phi1, and (iii) Φ=1\Phi=1.Comment: 25 pages, 15 figure

    Topology in thermodynamics of regular black strings with Kaluza-Klein reduction

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    We study the topological defects in the thermodynamics of regular black strings (from a four-dimensional perspective) that is symmetric under the double Wick rotation and constructed in the high-dimensional spacetime with an extra dimension compactified on a circle. We observe that the thermodynamic phases of regular black strings can be topologically classified by the positive and negative winding numbers (at the defects) which correspond to the thermodynamically stable and unstable branches. This topological classification implies a phase transition due to the decay of a thermodynamically unstable regular black string to another which is thermodynamically stable. We confirm these topological properties of the thermodynamics of regular black strings by investigating their free energy, heat capacity, and Ruppeiner scalar curvature of the state space. The Ruppeiner scalar curvature of regular black strings is found to be always negative, implying that the interactions among the microstructures of regular black strings are only attractive.Comment: 21 pages, 10 figure

    Well-Rounded ideal lattices of cyclic cubic and quartic fields

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    In this paper, we find criteria for when cyclic cubic and cyclic quartic fields have well-rounded ideal lattices. We show that every cyclic cubic field has at least one well-rounded ideal. We also prove that there exist families of cyclic quartic fields which have well-rounded ideals and explicitly construct their minimal bases. In addition, for a given prime number pp, if a cyclic quartic field has a unique prime ideal above pp, then we provide the necessary and sufficient conditions for that ideal to be well-rounded. Moreover, in cyclic quartic fields, we provide the prime decomposition of all odd prime numbers and construct an explicit integral basis for every prime ideal.Comment: 26 page
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