English

The Picard group of motivic A(1)

Algebraic Topology 2016-06-17 v1

Abstract

We show that the Picard group Pic(A(1))Pic(A(1)) of the stable category of modules over C\mathbb{C}-motivic A(1)A(1) is isomorphic to Z4\mathbb{Z}^4. By comparison, the Picard group of classical A(1)A(1) is Z2Z/2\mathbb{Z}^2 \oplus \mathbb{Z}/2. One extra copy of Z\mathbb{Z} arises from the motivic bigrading. The joker is a well-known exotic element of order 22 in the Picard group of classical A(1)A(1). The C\mathbb{C}-motivic joker has infinite order.

Keywords

Cite

@article{arxiv.1606.05191,
  title  = {The Picard group of motivic A(1)},
  author = {Bogdan Gheorghe and Daniel C. Isaksen and Nicolas Ricka},
  journal= {arXiv preprint arXiv:1606.05191},
  year   = {2016}
}