HACETTEPE JOURNAL OF MATHEMATICS AND STATISTICS, vol.48, no.5, pp.1388-1397, 2019 (SCI-Expanded)
In this paper, we introduce the notion of a group-2-groupoid as a group object in the category of 2-groupoids. We also obtain a 2G-crossed module by using the structure of a group-2-groupoid. Then we prove that the category GP2GD of group-2-groupoids and the category 2GXMoD of 2G-crossed modules are equivalent.