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# Nike Free Powerlines 2 Uk manifolds having distinct constant principal Ricci

We study three-dimensional pseudo-Riemannian manifolds having distinct constant principal Ricci curvatures. Nike Free Powerlines 2 Uk These spaces are described via a system of differential equations, and a simple characterization is proved to hold for the locally homogeneous ones. We then generalize the technique used in [O. Kowalski, F. Prüfer, On Riemannian Womens Nike Roshe Run 3-manifolds with distinct constant Ricci eigenvalues, Math. Ann. 300 (1994) 17–28] for Riemannian manifolds and construct explicitly homogeneous and non-homogeneous pseudo-Riemannian metrics in R3R3, having the prescribed principal Ricci curvatures.
An adequate set of temporal connectives for CTL is a subset of the logic's temporal connectives that is sufficient to express equivalents for all CTL formulas.In this paper, a characterization of all such adequate sets is presented. Specifically, it is shown that a subset of CTL's temporal connectives is adequate if and only if it contains one of {AX, EX}, one of {EG, AF, AU}, and EU.The proof requires, among other things, the analysis of a certain class of models, the reflexive models. These models have the desirable property that several connectives become redundant, thus simplifying the analysis.