Using an analytical model, we investigate the dynamics of a firm with market power whose advertisements and sales contribute to its customers’ stock of goodwill. An advertising campaign precedes the firm’s sales when customers are not familiar with its product, (e.g., movies), whereas sales...

We discuss here in detail a new analytical random walk approach to calculating the phase diagram for spatially extended systems with multiplicative noise. We use the Anderson localization problem as an example. The transition from delocalized to localized states is treated as a generalized...