9. A system comprising: one or more devices, including at least one memory and at least one processor, to: receive a document; select terms from the received document to form a plurality of term groups for the received document, each term group, of the plurality of term groups, being associated with an indication that a first term, of the term group, occurs before a second term, of the term group, within the received document; identify, from an inverted index of term groups, one or more clusters of a plurality of clusters, each cluster, of the one or more identified clusters, comprising a set of term groups for a respective other document, each respective term group, of the set of term groups, being associated with an indication that a first term, of the respective term group, occurs before a second term, of the respective term group, within the respective other document; determine measures of similarity between the plurality of term groups for the received document and the set of term groups for each of the one or more identified clusters; and determine, based on the determined measures of similarity, that the received document is similar to the respective other document.
9. A system comprising: one or more devices, including at least one memory and at least one processor, to: receive a document; select terms from the received document to form a plurality of term groups for the received document, each term group, of the plurality of term groups, being associated with an indication that a first term, of the term group, occurs before a second term, of the term group, within the received document; identify, from an inverted index of term groups, one or more clusters of a plurality of clusters, each cluster, of the one or more identified clusters, comprising a set of term groups for a respective other document, each respective term group, of the set of term groups, being associated with an indication that a first term, of the respective term group, occurs before a second term, of the respective term group, within the respective other document; determine measures of similarity between the plurality of term groups for the received document and the set of term groups for each of the one or more identified clusters; and determine, based on the determined measures of similarity, that the received document is similar to the respective other document. 15. The system of claim 9 , where the first term of the term group and the second term of the term group are non-consecutive in at least some term groups of the plurality of term groups.