Weather map motion. Two-dimensional streamlines based on wind speeds at various levels show areas of convergence and divergence in the wind field, which are helpful in determining the location of features within the wind pattern. A popular type of surface weather map is the surface weather analysis, which plots isobars to depict areas of high pressure and low pressure. Cloud codes are translated into symbols and plotted on these maps along with other meteorological data that are included in synoptic reports sent by professionally trained observers. The use of weather charts in a modern sense began in the middle portion of the
Single crossing condition ordered set. Such situations appear often in information economics, contract theory, social choice and political economics, among other fields. The term Single-Crossing Condition (Spence Mirrlees property) refers to the requirement that the isoutility curve for agents of different types cross only once. This condition guarantees that the transfer in a incentive-compatible direct mechanism can be pinned down by the transfer of the lowest type. This condition is similar to another condition called Strict Increasing Difference (SID). Formally, suppose the agent has a utility function formula_7, the SID says formula_8 we have formula_9. The Spence-Mirrlees Property is characterized by formula_10. Single