Nonpositive data

Nonpositive data refers to a database type.

In Nonpositive data, the negative image of a set of data records is represented rather than the records themselves. For now we assume a universe U of finite-length records (or strings), all of the same length l, and defined over a binary alphabet. We logically divide the space of possible strings into two disjoint sets: DB representing the set nonpositive data (holding the information of interest), and U - DB denoting the set of all strings not in DB. We assume that DB is uncompressed (each record is represented explicitly), but we allow U - DB to be stored in a compressed form called NDB. We refer to DB as the nonpositive data database and NDB as the negative database.