Double products and hypersymplectic structures on R4nR^{4n}

In this paper we give a procedure to construct hypersymplectic structures on $R^{4n}$ beginning with affine-symplectic data on $R^{2n}$. These structures are shown to be invariant by a 3-step nilpotent double Lie group and the resulting metrics are complete and not necessarily flat. Explicit examples of this construction are exhibited

Weak Mirror Symmetry of Complex Symplectic Algebras

A complex symplectic structure on a Lie algebra \lie h is an integrable complex structure $J$ with a closed non-degenerate $(2,0)$-form. It is determined by $J$ and the real part $\Omega$ of the $(2,0)$-form. Suppose that \lie h is a semi-direct product \lie g\ltimes V, and both \lie g and $V$ are Lagrangian with respect to $\Omega$ and totally real with respect to $J$. This note shows that \lie g\ltimes V is its own weak mirror image in the sense that the associated differential Gerstenhaber algebras controlling the extended deformations of $\Omega$ and $J$ are isomorphic. The geometry of $(\Omega, J)$ on the semi-direct product \lie g\ltimes V is also shown to be equivalent to that of a torsion-free flat symplectic connection on the Lie algebra \lie g. By further exploring a relation between $(J, \Omega)$ with hypersymplectic algebras, we find an inductive process to build families of complex symplectic algebras of dimension $8n$ from the data of the $4n$-dimensional ones.Comment: 22 page

110 common errors in company valuations

This paper contains a classified collection of 110 errors seen in company valuations performed by financial analysts, investment banks and financial consultants. The author had access to most of the valuations referred to in this paper in his capacity as a consultant in company acquisitions, sales, mergers, and arbitrage processes. We classify the errors into six main categories: 1) errors in the discount rate calculation and concerning the riskiness of the company; 2) errors when calculating or forecasting the expected cash flows; 3) errors in the calculation of the residual value; 4) inconsistencies and conceptual errors; 5) errors when interpreting the valuation; and 6) organizational errors.company valuation; valuation errors; valuation;

Flux switching alternators for small wind generation

This paper considers the application of flux switching alternators for small wind generation. First, after a brief presentation of the small wind energy systems, a description and the fundamentals of flux switching machines is given, then the state of art of flux switching generators is presented. Finally a critical assessment is shown, considering the main advantages and drawbacks of this type of machines as alternator for use in small wind generation systems.Peer ReviewedPostprint (published version