Dependencies between attributes of a database relation express the presence of
structure in that relation, that can be utilised in the database design process. In
particular, the existence of a multivalued dependency structure of relation r explicit. Furthermore, the new representation requires less
storage space than the complete relation r.Traditionally, database dependencies were considered to be part of the data
model provided by the database designer. However, they may also be retrieved
from the extensional data. One reason for doing so can be that the data model,
or parts of it, has been lost or is no longer accurate, so that some form of reverse
engineering is required. Another reason may be that certain dependencies were
not foreseen by the database designer, but do occur in practice. Once they
have been discovered, they may be utilised for restructuring the database, as
indicated above, but also for query optimisation. In this paper we address this
problem of multivalued dependency discovery, understood as characterising the
set of multivalued dependencies that are satised by a given collection of data.2