For any body-time manifold $\mathbb{ R} \times \mathcal{ B}$ there exists a groupoid, called material groupoid, encoding all the material properties of the evolution material. A smooth distribution, the material distribution, is constructed to deal with the case in which the material groupoid is not a Lie groupoid. This new tool provides a unified framework to deal with general non-uniform evolution materials.
Categories: math-ph math.DG math.MP