In this work, we define an exact generalized process and we establish some results such as monotonicity, compactness, and upper semicontinuity for the multivalued process defined by the exact generalized process. The main result is on compactness, invariance, and attraction properties of ω-limit sets.Keywords Nonautonomous dynamical systems · Pullback attraction · Generalized processes · Multivalued processes IntroductionThe concept of attraction is fundamental to analyze the asymptotic behavior of solutions of partial differential equations or inclusions. See, for example, [1][2][3][4][5][6][7][8][9][10][11]19] for autonomous, [12][13][14][15][16][17] for nonautonomous and [18,19] for stochastic problems. A concept which has been used a lot in the last years to deal with nonautonomous problems is pullback attraction, which attracts the solutions of the problem from −∞, i.e., the initial time goes to −∞ while the final time remains fixed [16,17,20]. The authors in [13] gave results which guarantee the existence of pullback attractors for processes, extending results of the autonomous case. In [21], the authors present abstract results that provide sufficient conditions to the existence of pullback attractors for multivalued processes. Observe that is also possible considering forward attractors for nonautonomous problems [22].

In this paper we study a Dirichlet-to-Neumann operator with respect to a second order elliptic operator with measurable coefficients, including first order terms, namely, the operator on L 2 (∂Ω) given by ϕ → ∂νu where u is a weak solution ofUnder suitable assumptions on the matrix-valued function a, on the vector fields b and c, and on the function d, we investigate positivity, sub-Markovianity, irreducibility and domination properties of the associated Dirichlet-to-Neumann semigroups.

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In this paper, we prove a stability result about the asymptotic dynamics of a perturbed nonautonomous evolution equation in R n governed by a maximal monotone operator.

A eficiência adquiriu maior relevância entre as organizações no cenário de mercados abertos, que teve início no Brasil, por volta dos anos 90. O objetivo deste artigo é analisar, por envoltória de dados, a eficiência dos aeroportos brasileiros, utilizando as bases de dados da Agência Nacional de Aviação Civil (ANAC) e Empresa Brasileira de Infraestrutura Aeroportuária (INFRAERO), dos períodos de 2009, 2010 e 2011. A técnica foi aplicada para os 16 aeroportos internacionais brasileiros, considerando variáveis financeiras. Os resultados apontaram que o porte de um aeroporto não foi determinante para atribuir a eficiência a cada um deles, embora seja critério relevante para impulsionar melhorias no desempenho dos mesmos. Convém salientar, também, que a utilização dos recursos (inputs) para o alcance do produto (output) foi o critério mais relevante na busca do bom desempenho e da eficiência aeroportuária no estudo aqui apresentado.