  We define a general framework that includes objects such as tilings, Delone
sets, functions and measures. We define local derivability and mutual local
derivability (MLD) between any two of these objects in order to describe their
interrelation. This is a generalization of the local derivability and MLD (or
S-MLD) for tilings and Delone sets which are used in the literature, under a
mild assumption. We show that several canonical maps in aperiodic order send an
object P to one that is MLD with P. Moreover we show that, for an object P and
a class S of objects, a mild condition on them assures that there exists some Q
in S that is MLD with P. As an application, we study pattern equivariant
functions. In particular, we show that the space of all pattern-equivariant
functions contains all the information of the original object up to MLD in a
quite general setting.
