Editing Utility (section)

===Examples===

In order to simplify calculations, various alternative assumptions have been made concerning details of human preferences, and these imply various alternative utility functions such as:

* [[constant elasticity of substitution|CES]] (''constant elasticity of substitution'').
* [[Isoelastic utility]]
* [[Exponential utility]]
* [[Quasilinear utility]]
* [[Homothetic preferences]]
* [[Stone–Geary utility function]]
* [[Gorman polar form]]
** [[Greenwood–Hercowitz–Huffman preferences]]
** [[King–Plosser–Rebelo preferences]]
* [[Hyperbolic absolute risk aversion]]

Most utility functions used for modeling or theory are '''well-behaved.''' They are usually monotonic and quasi-concave. However, it is possible for rational preferences not to be representable by a utility function. An example is [[lexicographic preferences]] which are not continuous and cannot be represented by a continuous utility function.<ref>{{cite book |first=Jonathan E. Jr. |last=Ingersoll |title=Theory of Financial Decision Making |url=https://archive.org/details/theoryoffinancia1987inge |url-access=registration |location=Totowa |publisher=Rowman and Littlefield |year=1987 |page=[https://archive.org/details/theoryoffinancia1987inge/page/21 21] |isbn=0-8476-7359-6 }}</ref>