[This paper presents general results on the existence and properties of expected-utility-maximizing search rules for problems in which searchers may choose both the number of periods in which samples are taken and the size of the sample taken in each period. These rules include fixed-sample-size rules and sequential rules as special cases. Also presented are conditions sufficient for sequential and fixed-sample-size rules to be optimal.]

With public consumption goods, Pareto optimality can be achieved in equilibrium through Lindahl pricing. This requires that each consumer pays a price proportional to his marginal utility from the public good. The marginal cost of providing the good is then equated to the sum of the marginal benefits. Some public goods serve as inputs into production processes rather than as consumption goods: the lighthouse is an example. Efficiency in an economy with public intermediate goods requires that the marginal cost of providing them equals the sum of their marginal benefits to firms. By analogy with the case of public consumption goods, it might seem that Lindahl pricing can be extended to public intermediate goods, by requiring that firms pay in proportion to the marginal contribution of these goods to profits. Agnar Sandmo (1972) explicitly proposes this for convex technologies. For nonconvex technologies that arise with an important class of production functions (essentially those exhibiting atmosphere externalities, in the phrase of James Meade, 1952), Lindahl pricing for such public inputs is infeasible. The principal result derived here is a sim