Peak uranium gold, silver, copper or nickel, uranium is not widely traded on an organized commodity exchange such as the London Metal Exchange. It is traded on the NYMEX but on very low volume. Instead, it is traded in most cases through contracts negotiated directly between a buyer and a seller. The structure of uranium supply contracts varies widely. The prices are either fixed or base on referenced to economic indices such as GDP, inflation or currency exchange. Contracts traditionally are based on the uranium spot price and rules by which the price can escalate. Delivery quantities, schedules, and prices vary from
Laplacian of the indicator Dirac -function, but as a function of the radial coordinate "r", e.g. δ("r"−"R") where "R" is the radius of the sphere. Although seemingly ill-defined, derivatives of the indicator function can formally be defined using the theory of distributions or generalized functions: one can obtain a well-defined prescription by postulating that the Laplacian of the indicator, for example, is defined by two integrations by parts when it appears under an integral sign. Alternatively, the indicator (and its derivatives) can be approximated using a bump function (and its derivatives). The limit, where the (smooth) bump function approaches the indicator function, must then