WordNet (r) 3.0 (2006):
logical relation n 1: a relation between propositionsThe Free On-line Dictionary of Computing (30 December 2018):
logical relation A relation R satisfying f R g <=> For all a, b, a R b => f a R g b This definition, by Plotkin, can be used to extend the definition of a relation on the types of a and b to a relation on functions.