# PlanetPhysics/Category of Representations

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The\htmladdnormallink{category{http://planetphysics.us/encyclopedia/Cod.html}Failed to parse (unknown function "\grp"): {\displaystyle Rep(\grp)}of representations} has objects the representations of a groupoidFailed to parse (unknown function "\grp"): {\displaystyle \grp}, and as morphisms theintertwinersthat are (vector) bundle morphisms over the manifold so that . Because representations are functorsFailed to parse (unknown function "\grp"): {\displaystyle \rho: \grp \longrightarrow {\mathbf Vect}}, an itertwiner is in fact a natural transformation between two such functors that are groupoid representations ofFailed to parse (unknown function "\grp"): {\displaystyle \grp}, in this case implemented {\it via} the vector bundle morphisms .