A closure associative processor

The authors describe a bidirectional associative processor that stores a hierarchy of entities and characteristics as an adjacency matrix. The matrix is unipolar binary, which allows it to be easily stored in a spatial light modulator and makes it attractive for optical implementation. A large hierarchy can be separated into subhierarchies and stored in separate processors. The authors discuss how the processor can perform upward and downward closure, union, intersection, and complementation with the aid of simple electronics (a register, thresholders, exclusive-OR and inverter gates). By combining series of these operations, the processor can answer nontrivial queries.<>