As nouns the difference between approximation and underapproximation
is that approximation
is the act, process or result of approximating while underapproximation
is an approximation that is lower than the true value.
Other Comparisons: What's the difference?
The act, process or result of approximating.
(mathematics) An imprecise solution or result that is adequate for a defined purpose.
(medicine) The act of bringing together the edges of tissue to be sutured.
* approximation problem
* approximation property
* approximation theory
An approximation that is lower than the true value.