  Mutual information in three (or more) dimensions can be considered as a
Triple-Helix indicator of synergy in university-industry-government relations.
An open-source routine th4.exe makes the computation of this indicator
interactively available at the Internet, and thus applicable to large sets of
data. Th4.exe computes all probabilistic entropies and mutual information in
two, three, and, if available in the data, four dimensions among, for example,
classes such as geographical addresses (cities, regions), technological codes
(e.g., OECD's NACE codes), and size categories; or, alternatively, among
institutional addresses (academic, industrial, public sector) in document sets.
The relations between the Triple-Helix indicator -- as an indicator of synergy
-- and the Triple-Helix model that specifies the possibility of feedback by an
overlay of communications, are also discussed.
