STRATEGIES FOR COMPRESSING INFORMATION USING BLOOM FILTERS

A strategy is described for constructing bloom filter information and exception information. The bloom filter information is constructed to express a set of items in a lossy compressed form. The exception information reveals occasions in which the bloom filter information erroneously indicates that a candidate item is a member of the set. The strategy can apply the bloom filter information and the exception information to select a representative device among a group of devices on which a user may maintain simultaneous presence.