In other words, the SC lattice without dislocation can be interpreted as the inverse image by \(\widehat {\psi }\) of a constant section \(\check \sigma _{\gamma }\) of the trivial S1-bundle. Using the multiplication, we have the following description of a parallel multi-screw dislocation in the BCC lattice. MATH  RAAG Memoirs. What is Edge Dislocation Note that \(\mathbb {Z}_{\mathbb {E}^{2}} = \mathbb {Z}\times \mathbb {E}^{2}\) is a covering space of \(\mathbb {E}^{2}\) and that \(\mathbb {E}_{\mathbb {E}^{2}}\) is identified with \(\mathbb {E}^{3} = \mathbb {E} \times \mathbb {E}^{2}\). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. which is a consequence of the exactness of (1). The role of screw dislocations is attributed to the changing nature of dislocation source operation at different strain rates. The total strain energy of a pair of screw dislocations whose dislocation lines are parallel to each other and correspond to \(\mathcal {S}_{+}=\{(x_{0}, y_{0})\}\) and \(\mathcal {S}_{-}=\{(x_{0}, -y_{0})\}\) with y0≠0, is well-known in the continuum picture as follows: where 0<ρ