Abstract: In one embodiment, a method includes receiving, from a client system associated with a user, a search query comprising a number of query terms, generating a query match-matrix for the search query, identifying a number of objects matching the search query, retrieving, for each identified object, an object match-matrix for the identified object, constructing, for each identified object, a three-dimensional tensor for the identified object, computing, for each identified object, a relevance score based on the tensor for the identified object, ranking the identified objects based on their respective relevance scores, and sending, to the first client system in response to the search query, instructions for generating a search-results interface for presentation to the user.

Abstract: In one embodiment, a method includes receiving, from a client system associated with a user, a search query comprising a number of query terms, generating a query match-matrix for the search query, identifying a number of objects matching the search query, retrieving, for each identified object, an object match-matrix for the identified object, constructing, for each identified object, a three-dimensional tensor for the identified object, computing, for each identified object, a relevance score based on the tensor for the identified object, ranking the identified objects based on their respective relevance scores, and sending, to the first client system in response to the search query, instructions for generating a search-results interface for presentation to the user.

Abstract: Controlling a registered-user session of a registered user on a device using first and second authentication processes and a handoff from the first process to the second process. In one embodiment, the first authentication process is a stronger process performed at the outset of a session, and the second authentication process is a weaker process iteratively performed during the session. The stronger authentication process may require cooperation from the user, while the weaker authentication process is preferably one that requires little or no user cooperation. In other embodiments, a strong authentication process may be iteratively performed during the session.