We consider three applications of impulse control in financial mathematics, a cash management problem, optimal control of an exchange rate, and portfolio optimisation under transaction costs. We sketch the different ways of solving these problems with the help of quasi-variational inequalities....

In a general semi-martingale financial market with possibly nonlinear wealth dynamics, incomplete information, and ambiguity, we show that the optimal consumption decision of an agent with logarithmic preferences can be separated from the agent's investment decisions. Using minimal assumptions...

In a discrete-time financial market setting, the paper relates various concepts introduced for dynamic portfolios (both in discrete and in continuous time). These concepts are: value preserving portfolios, numeraire portfolios, interest oriented portfolios, and growth optimal portfolios. It will...