Operator Types

An operator expresses an operation that is applied to a part of the search expression. This operation defines the restrictions a document must meet in order to be placed in the resulting list of hits. Many operators exist, and they can be classified according to their type:

Standard Operators

  • Concept operators
  • Evidence operators
  • Proximity operators

Special operators

  • Operators for analyzing written language
  • Ranking operators
  • Field operators and relational operators