English

A blueprinted view on $\mathbb F_1$-geometry

Algebraic Geometry 2013-06-07 v2 Combinatorics K-Theory and Homology Number Theory Representation Theory

Abstract

This overview paper has two parts. In the first part, we review the development of F1\mathbb F_1-geometry from the first mentioning by Jacques Tits in 1956 until the present day. We explain the main ideas around F1\mathbb F_1, embedded into the historical context, and give an impression of the multiple connections of F1\mathbb F_1-geometry to other areas of mathematics. In the second part, we review (and preview) the geometry of blueprints. Beyond the basic definitions of blueprints, blue schemes and projective geometry, this includes a theory of Chevalley groups over F1\mathbb F_1 together with their action on buildings over F1\mathbb F_1; computations of the Euler characteristic in terms of F1\mathbb F_1-rational points, which involve quiver Grassmannians; KK-theory of blue schemes that reproduces the formula Ki(F1)=πist(S0)K_i(\mathbb F_1)=\pi^{st}_i(S^0); models of the compactifications of \SpecZ\Spec \mathbb Z and other arithmetic curves; and explanations about the connections to other approaches towards F1\mathbb F_1 like monoidal schemes after Deitmar, B1B_1-algebras after Lescot, Λ\Lambda-schemes after Borger, relative schemes after To\"en and Vaqui\'e, log schemes after Kato and congruence schemes after Berkovich and Deitmar.

Cite

@article{arxiv.1301.0083,
  title  = {A blueprinted view on $\mathbb F_1$-geometry},
  author = {Oliver Lorscheid},
  journal= {arXiv preprint arXiv:1301.0083},
  year   = {2013}
}

Comments

58 pages; correction of section 7.2 and other minor modifications

R2 v1 2026-06-21T23:02:34.906Z