%0 Journal Article %T Quadratic variation, p-variation and integration with applications to stock price modelling %A Rimas Norvaisa %J Mathematics %D 2001 %I arXiv %X The paper develops a calculus for a class of real-valued functions having a quadratic variation. The main result is a solution of the representation problem for a class of evolutions having a quadratic variation. The result is applied to build up an asset pricing model. Also in the paper there are some results concerning an extension of the class of all semimartingales. %U http://arxiv.org/abs/math/0108090v1