  Starting from the Boolean notion of logical proportion in Piaget's sense,
which turns out to be equivalent to analogical proportion, this note proposes a
definition of analogical proportion between numerical values based on
triangular norms (and dual co-norms). Frank's family of triangular norms is
particularly interesting from this perspective. The article concludes with a
comparative discussion with another very recent proposal for defining
analogical proportions between numerical values based on the family of
generalized means.
