Comparison (mathematical)

An approximation is anything that is intentionally similar but not exactly equal to something else.

thumb|LM393 dual comparator, a common comparator integrated circuit chip, shown on a circuit board

A ranking is a relationship between a set of items, often recorded in a list, such that, for any two items, the first is either "ranked higher than", "ranked lower than", or "ranked equal to" the second. In mathematics, this is known as a weak order or total preorder of objects. It is not necessarily a total order of objects because two different objects can have the same ranking. The rankings themselves are totally ordered. For example, materials are totally preordered by hardness, while degrees of hardness are totally ordered. If two items are the same in rank it is considered a tie.

comparison of topologies induced by the partial ordering on topologies on any given set

programming language construct or operator that tests or defines some kind of relation between two entities

statistical data type