Preferences that have a single maximum over a linearly ordered set of alternatives. A set of alternatives can be linearly ordered if it is possible to arrange them along a one-dimensional axis. For example, the location of shops on one side of a street is linearly ordered. Preferences are single-peaked if there is a unique most-preferred point on the axis, and the valuation of other alternatives declines monotonically away from the most-preferred point in either direction. This means that any individual asked to choose or vote will always prefer the most-valued level to any other, and, of any two alternatives on the same side of the most preferred value, will vote for that nearer the preferred value.