Algebraic & Geometric Topology
- Algebr. Geom. Topol.
- Volume 18, Number 2 (2018), 635-685.
A motivic Grothendieck–Teichmüller group
We prove the Beilinson–Soulé vanishing conjecture for motives attached to the moduli spaces of curves of genus with marked points. As part of the proof, we also show that these motives are mixed Tate. As a consequence of Levine’s work, we thus obtain a well-defined category of mixed Tate motives over the moduli space of curves . We furthermore show that the morphisms between the moduli spaces obtained by forgetting marked points and by embedding boundary components induce functors between the associated categories of mixed Tate motives. Finally, we explain how tangential base points fit into these functorialities.
The categories we construct are Tannakian, and therefore have attached Tannakian fundamental groups, connected by morphisms induced by those between the categories. This system of groups and morphisms leads to the definition of a motivic Grothendieck–Teichmüller group.
The proofs of the above results rely on the geometry of the tower of the moduli spaces . This allows us to treat the general case of motives over with coefficients in , working in Spitzweck’s category of motives. From there, passing to coefficients, we deal with the classical Tannakian formalism and explain how working over yields a more concrete description of the Tannakian groups.
Algebr. Geom. Topol., Volume 18, Number 2 (2018), 635-685.
Received: 13 April 2015
Revised: 31 August 2017
Accepted: 30 October 2017
First available in Project Euclid: 22 March 2018
Permanent link to this document
Digital Object Identifier
Mathematical Reviews number (MathSciNet)
Zentralblatt MATH identifier
Primary: 14F42: Motivic cohomology; motivic homotopy theory [See also 19E15] 14J10: Families, moduli, classification: algebraic theory 19E15: Algebraic cycles and motivic cohomology [See also 14C25, 14C35, 14F42]
Secondary: 14F05: Sheaves, derived categories of sheaves and related constructions [See also 14H60, 14J60, 18F20, 32Lxx, 46M20]
Soudères, Ismaël. A motivic Grothendieck–Teichmüller group. Algebr. Geom. Topol. 18 (2018), no. 2, 635--685. doi:10.2140/agt.2018.18.635. https://projecteuclid.org/euclid.agt/1521684012