We introduce a new string matching problem called order preserving matching on numeric strings, where a pattern matches a text substring if the relative orders between numbers in the substring coincide with those of the pattern.

Order preserving matching is applicable to many scenarios such as stock price analysis and musical melody matching in which order relations should be matched rather than strings themselves. Solving order preserving matching is closely related to the representation of order relations in a numeric string. We define the prefix representation and the nearest neighbor representation of the pattern, both of which lead to efficient algorithms for order preserving matching.

Following this work, there has recently been active research on many variants of order preserving matching.