Pareto - guaranteed equilibrium in Hotelling's duopoly on the plane

In this paper we study Hotelling’s duopoly under uncertainty. On a single square are located two firms, which claim the price of the goods. At same time, on the proposed firms product is introduced excise tax, the value of which is not known in advance and is uncertainty. One of the firms increases the value of the goods at the amount of excise tax, and the other does not change. Buyers make a firm choice, comparing costs of its visit which represent the price and distance sum. There is a decision Pareto - guaranteed equilibrium.