nLab Sullivan construction




The Sullivan construction constructs a (rational) topological space from a dg-algebra (a graded commutative cochain dg-algebra in positive degree).

This is the special case of the construction of differential forms on presheaves from the definition of polynomial differential forms on simplices.

It is one part of an equivalence of categories between the homotopy category of (connected, simply connected) dg-algebras and that of (simply connected) rational topological spaces. As such it is a central tool in rational homotopy theory.


Let Δ Diff:Δ\Delta_{Diff} : \Delta \to Diff be the standard smooth simplexes, and write Ω (Δ Diff n)\Omega^\bullet_{\mathbb{Q}}(\Delta_{Diff}^n) for the dg-algebra of (polynomial, rational, whatevber) differential forms on Δ Diff n\Delta^n_{Diff}.

For AdgAlg A \in dgAlg_{\mathbb{Q}} a dg-algebra, consider the simplicial set

|A|:[n]Hom dgAlg op(Ω (Δ Diff n),A). |A| : [n] \mapsto Hom_{dgAlg^{op}}( \Omega^\bullet(\Delta^n_{Diff}), A) \,.

This, or rather its geometric realization to a rational topological space, is the Sullivan construction.


See the references at rational homotopy theory.

Last revised on July 23, 2018 at 20:05:57. See the history of this page for a list of all contributions to it.