Universal enveloping algebras and loop space homology
If \(R\) is a principal ideal domain such that \(H_ *(\Omega X; R)\) is torsion free then \(H_ *(\Omega X; R)\) is a graded cocommutative Hopf algebra. The submodule \(P \subset H_ *(\Omega X;R)\) of primitive elements is a subgraded Lie algebra and the inclusion extends to a Hopf algebras homomorphism \[ \Phi: UP \to H_ *(\Omega X; R). \] In [Ann. Math., II. Ser. 81, 211-264 (1965; Zbl 0163.282)], \textit{J. W. Milnor} and \textit{J. C. Moore} show that if \(X\) is simply connected and \(R = Q\) then \(\Phi\) is an isomorphism. The first result of this paper is to extend this result to more general coefficient rings, at the cost of restricting the class of spaces \(X\). The second result consists to associate functorially to each space \(X\) in a certain class of spaces a graded Lie algebra \(L\) over \(\mathbb{F}_ p\) such that there exists a natural isomorphism of Hopf algebras \[ UL @>\cong>> H_ *(\Omega X;\mathbb{F}_ p). \] This theorem represents a considerable strengthening of a result of \textit{D. J. Anick} [J. Am. Math. Soc. 2, No. 3, 417-453 (1989; Zbl 0681.55006)] which asserts that \(H_ *(\Omega X;\mathbb{F}_ p)\) is primitively generated.
scientific article; zbMATH DE number 166156
scientific article