The vast majority of wind turbines that are currently being installed use one of the three main types of electromechanical conversion system. The first type is known as the Danish concept. The second type uses a doubly fed induction generator instead of a squirrel cage induction generator. The third type is called the ‘direct-drive wind turbine’ because it does not need a gearbox. In this paper...

We construct an index theorem for smooth infinite economies that shows that generically the number of equilibria is odd. As a corollary, this gives a new proof of existence and gives conditions that guarantee global uniqueness of equilibria.

We present a simple proof of existence of subgame perfect equilibria in games with perfect information.

Lévy driven term structure models have become an important subject in the mathematical finance literature. This paper provides a comprehensive analysis of the Lévy driven Heath–Jarrow–Morton type term structure equation. This includes a full proof of existence and uniqueness in particular, which seems to have been lacking in the finance literature so far.

Let Ω be a smooth bounded simply connected domain in R2. We investigate the existence of critical points of the energy Eε(u) = 1/2 ́ Ω |∇u|2 + 1/(4ε2) ́ Ω(1−|u|), where the complex map u has modulus one and prescribed degree d on the boundary. Under suitable nondegeneracy assumptions on Ω, we prove existence of critical points for small ε. More can be said when the prescribed degree equals one. ...