Abstract: A computer memory stores a data structure representing a ternary search tree (TST) representing multiple word n-grams for a corpus of documents. The data structure includes plural records in a first memory, each record representing a node of the TST and comprising plural fields. At least some n-grams have a sequence of units. The plurality of fields includes one for identifying a given unit of the sequence for a given node, one reserved for storing payload information for the given node, and plural child fields reserved for storing information for a first, second and third child nodes of the given node. The child fields store a null value indicating the absence of the child node or an identifier identifying a memory location of the child node. For at least one record, at least one of the child fields stores an identifier identifying a memory location of a memory different than the first memory.

Abstract: A computer memory stores a data structure representing a ternary search tree (TST) representing multiple word n-grams for a corpus of documents. The data structure includes plural records in a first memory, each record representing a node of the TST and comprising plural fields. At least some n-grams have a sequence of units. The plurality of fields includes one for identifying a given unit of the sequence for a given node, one reserved for storing payload information for the given node, and plural child fields reserved for storing information for a first, second and third child nodes of the given node. The child fields store a null value indicating the absence of the child node or an identifier identifying a memory location of the child node. For at least one record, at least one of the child fields stores an identifier identifying a memory location of a memory different than the first memory.

Abstract: An interactive method for searching a database to produce a refined results space, the method comprising: analyzing for search criteria, searching said database using said search criteria to obtain an initial result space, and obtaining user input to restrict said initial results space, thereby to obtain said refined results space. Refining comprises using classifications of the retrieved data items to formulate prompts for the user, asking said user at least one of the formulated prompts and receiving a response thereto; and using responses in conjunction with classification values to exclude some of the results, thereby to provide to the user a subset of the retrieved data items as a query result.