Prompt by the fact that Noll’s theory is ultimately a theory describing dislocations into solids, we propose
a way for defining continuous distribution of dislocations for objective structures. But, objective structures
are discrete in nature, thereby making notions such as derivatives only intuitively defined. The remedy of this
comes from the important work of Ariza and Ortiz [1] that use notions from algebraic topology and discrete
exterior calculus [19,23] to describe crystal elasticity. We give the discrete analog of a material isomorphism
and thereby of a materially uniform discrete body. This way we may present a definition similar to the one given
by Noll, but for discrete structures. The definition given by Ariza and Ortiz [1] is in similar terms with ours,
but these authors refrain from using the notion of a material isomorphism. Also, our approach is not restricted
to geometrical or material linearities. Interestingly, it turns out that discrete material uniformity corresponds
to elements of the symmetry group of objective structures; thus, following Noll’s recipe, we are able to define
dislocations for objective structures. This appears to be the basic novelty of the present contribution.
The paper is structured as follows. Section2contains four subsections. The first describes the theory of
objective structures, while the second the theory of materially uniform bodies. The third subsection introduces
the micromorphic approach utilized in this work. In the final subsection, we highlight similarities as well as
differences between objective structures and materially uniform bodies. Section3consists of the study of
continuous distribution of dislocations and is divided in three subsections. The first one is a reminder of Noll’s
notion of inhomogeneity. The second describes the important work of Ariza and Ortiz [1] for modeling crystal
elasticity. The final subsection introduces the discrete notion of the material isomorphism and ultimately the
definition of continuous distribution of dislocations for objective structures. Section4concludes with some
remarks as well as some future directions.