English

Positive motivic measures are counting measures

Algebraic Geometry 2009-07-06 v1

Abstract

Let K be a field. A positive motivic measure on the Grothendieck ring K_0(Var_K) is a homomorphism from K_0(Var_K) to the real numbers assigning a nonnegative value to every variety. In this note we show that the only positive motivic measures are the counting measures: measures on K_0(Var_{F_q}) which send a variety to its number of rational points over some fixed finite extension of F_q.

Cite

@article{arxiv.0907.0488,
  title  = {Positive motivic measures are counting measures},
  author = {Jordan S. Ellenberg and Michael Larsen},
  journal= {arXiv preprint arXiv:0907.0488},
  year   = {2009}
}

Comments

5 pages

R2 v1 2026-06-21T13:20:45.312Z