Closed form approximations to the fundamental solution of parabolic PDEs is considered. The approach consists on approximations based on a parametrix series expansion. The approximation error can be bounded by a gaussian function and it is of an order of t^2. These explicit expressions have...

We propose a general class of non-constant volatility models with dependence on the past. The framework includes path-dependent volatility models such as that by Hobson&Rogers and also path dependent contracts such as options of Asian style. A key feature of the model is that market completeness...