PlanetPhysics/Groupoid Action

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Let Failed to parse (unknown function "\grp"): {\displaystyle \grp}
 be a groupoid and  a topological space. A groupoid action , or Failed to parse (unknown function "\grp"): {\displaystyle \grp}
-action, on  is given by two maps: the anchor map   and a map  with the latter being defined on pairs  such that , written as . The two maps are subject to the following conditions:
  • and
  • whenever the operations are defined.

{\mathbf Note:} The groupoid action generalizes the concept of group action in a non-trivial way