Geometry & Topology

Grothendieck ring of semialgebraic formulas and motivic real Milnor fibers

Georges Comte and Goulwen Fichou

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We define a Grothendieck ring for basic real semialgebraic formulas, that is, for systems of real algebraic equations and inequalities. In this ring the class of a formula takes into consideration the algebraic nature of the set of points satisfying this formula and this ring contains as a subring the usual Grothendieck ring of real algebraic formulas. We give a realization of our ring that allows us to express a class as a [12]–linear combination of classes of real algebraic formulas, so this realization gives rise to a notion of virtual Poincaré polynomial for basic semialgebraic formulas. We then define zeta functions with coefficients in our ring, built on semialgebraic formulas in arc spaces. We show that they are rational and relate them to the topology of real Milnor fibers.

Article information

Geom. Topol., Volume 18, Number 2 (2014), 963-996.

Received: 4 September 2012
Revised: 10 October 2013
Accepted: 14 November 2013
First available in Project Euclid: 20 December 2017

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Mathematical Reviews number (MathSciNet)

Zentralblatt MATH identifier

Primary: 14P10: Semialgebraic sets and related spaces
Secondary: 14B05: Singularities [See also 14E15, 14H20, 14J17, 32Sxx, 58Kxx] 14P25: Topology of real algebraic varieties

Grothendieck ring semialgebraic sets motivic Milnor fiber


Comte, Georges; Fichou, Goulwen. Grothendieck ring of semialgebraic formulas and motivic real Milnor fibers. Geom. Topol. 18 (2014), no. 2, 963--996. doi:10.2140/gt.2014.18.963.

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