homotopy double groupoid of a Hausdorff space
Homotopy double groupoid of a Hausdorff space
Let be a Hausdorff space. Also consider the HDA concept of a double groupoid (http://planetmath.org/HigherDimensionalAlgebraHDA), and how it can be completely specified for a Hausdorff space, . Thus, in ref. [BHKP] Brown et al. associated to a double groupoid, , called the homotopy double groupoid of X which is completely defined by the data specified in Definitions 0.1 to 0.3 in this entry and related objects.