and rational homotopy theory (equivariant, stable, parametrized, equivariant & stable, parametrized & stable) representation, 2-representation, ∞-representation Grothendieck group, lambda-ring, symmetric function, formal group principal bundle, torsor, vector bundle, Atiyah Lie algebroid Eilenberg-Moore category, algebra over an operad, actegory, crossed module What may be called Borel-equivariant rational homotopy theory (this is not an established term, but it fits well) is the rational...