Abstract: A method and a processing device are provided for compressing a web graph including multiple nodes and links between the multiple nodes. Nodes of the web graph may be clustered into groups including no more than a predetermined number of nodes. A list of links of the clustered nodes may be created and sorted based on a frequency of occurrence of each of the links. A prefix tree may be created based on the sorted list of links. The prefix tree may be walked to find candidate virtual nodes. The candidate virtual nodes may be analyzed according to a selection criteria and a virtual node may be selected. The prefix tree may be adjusted to account for the selection of the virtual node and the virtual node may be added to the web graph.

Abstract: A processing device and method may be provided for determining whether a zero search result may be produced with respect to a search for a document including all words of a word group. An index, with respect to words included in a group of documents, may be searched for documents including all words of the word group when a zero search result is determined not likely to occur with respect to the search for the document including all of the words of the word group. A method for creating multiple types of data structures corresponding to word grouping collections may further be provided to store occurrence information indicating a likelihood of a presence of a document including all words of a word group.

Abstract: Technologies are described herein for constructing a minimal perfect hash function. According to embodiments, a hash table is constructed by double hashing each of the strings in a set of strings. A computed double hash value is utilized to identify an empty location in the hash table for each string. A signature for each string is stored in the empty location of the hash table identified for the string. In order to obtain a minimal perfect hash value for an input string, the input string is iteratively double hashed until a location is identified in the hash table that contains a signature corresponding to the input string. The minimal perfect hash value is an integer value identifying the location in the hash table that contains the signature corresponding to the input string.