nLab Mumford's conjecture





Special and general types

Special notions


Extra structure



Complex geometry



A conjecture in (Mumford 83) concerned the ordinary cohomology with rational numbers coefficients of the classifying space of the stable mapping class group, which is essentially the stable orbifold cohomology of the moduli stack of curves over the complex numbers.

The conjecture was proven in (Madsen-Weiss 02).

Exposition and review is in (Madsen 07).


The conjecture is due to

  • David Mumford, Towards an enumerative geometry of the moduli space of curves, In Arithmetic and geometry, Vol. II, Progr. Math. 36, Birkhäuser, Boston, MA, 1983, 271–328.

The proof is due to

See also

  • Geoffrey Powell, The Mumford conjecture (after Madsen and Weiss), Séminaire Bourbaki. Vol. 2004/2005. Astérisque 307 (2006), Exp. No. 944, viii, 247–282, MR2009f:55018

  • Michael Weiss, Cohomology of the stable mapping class group, Topology, geometry and quantum field theory, 379–404, London Math. Soc. Lecture Note Ser. 308, Cambridge Univ. Press 2004, MR2005e:57059

  • Ib Madsen, Ulrike Tillmann, The stable mapping class group and Q(CP + )Q(\mathbf{C} P^\infty_+), Invent. Math. 145 (2001), no. 3, 509–544. MR2002h:55011

Review and exposition is in

  • Ib Madsen, Moduli spaces from a topological viewpoint, Proceedings of the International Congress of Mathematics, Madrid 2006 (2007) (pdf)

Last revised on July 16, 2014 at 03:40:20. See the history of this page for a list of all contributions to it.