Let the Ornstein–Uhlenbeck process $$(X_t)_{t\ge 0}$$ driven by a fractional Brownian motion $$B^{H }$$ described $$dX_t = -\theta X_t dt + \sigma dB_t^{H be observed at discrete time instants $$t_k=kh$$ , $$k=0, 1, 2, \ldots 2n+2 $$ . We propose an ergodic type statistical estimator $${\hat{\theta }}_n $${\hat{H}}_n and $${\hat{\sigma to estimate all parameters $$\theta H $$\sigma in above mod...

six sigma methodology is one of the most famous effective problem solving approaches that helps organizations to achieve their goals. despite the variety of its positive advantage, most companies have failed to implement six sigma successfully. the reason for this includes lack of the organizations attention to success or failure factors when implement six sigma projects. hence, while performin...

This paper discusses beta and sigma convergence of commercial, savings, and cooperative banks in the Eurozone from 1999 to 2012. For this purpose, concepts of the growth and efficiency convergence literature are consulted and GMM, fixed effects models, and OLS are applied. Convergence is analyzed by calculating two efficiency metrics – data envelopment analysis (DEA) and stochastic frontier ana...

We generalize the respective “double recurrence” results of Bourgain and of the second author, which established for pairs of L∞ functions on a finite measure space the a.e. convergence of the discrete bilinear ergodic averages and of the discrete bilinear Hilbert averages defined by invertible measure-preserving point transformations. Our generalizations are set in the context of arbitrary sig...

South Africa is characterized by significant inequality in spatial economic activity. Whether future growth and development on a subnational level in South Africa will be such as to reduce this inequality may depend on the economic growth and development of South Africa’s largest cities. Our local economic growth empirics show some indications of conditional convergence in output between poorer...

South Africa is characterized by significant inequality in spatial economic activity. Whether future growth and development on a subnational level in South Africa will be such as to reduce this inequality may depend on the economic growth and development of South Africa’s largest cities. Our local economic growth empirics show some indications of conditional convergence in output between poorer...

Let $S(G^{sigma})$ be the skew-adjacency matrix of the oriented graph $G^{sigma}$, which is obtained from a simple undirected graph $G$ by assigning an orientation $sigma$ to each of its edges. The skew energy of an oriented graph $G^{sigma}$ is defined as the sum of absolute values of all eigenvalues of $S(G^{sigma})$. Two oriented graphs are said to be skew equienergetic iftheir skew energies...

Let $mathcal{A}$ be a Banach algebra and $mathcal{M}$ be a Banach $mathcal{A}$-bimodule. We say that a linear mapping $delta:mathcal{A} rightarrow mathcal{M}$ is a generalized $sigma$-derivation whenever there exists a $sigma$-derivation $d:mathcal{A} rightarrow mathcal{M}$ such that $delta(ab) = delta(a)sigma(b) + sigma(a)d(b)$, for all $a,b in mathcal{A}$. Giving some facts concerning general...