English

Real Global Group Laws and Hu-Kriz Maps

Algebraic Topology 2025-01-13 v1

Abstract

Recently, Hausmann defined global group laws and used them to prove that MUGMU^G_* is the GG-equivariant Lazard ring, for GG a compact abelian Lie group. On the other hand, Hu and Kriz showed that the restriction map induces an isomorphism MRρC2MU2M \mathbb{R}^{C_2}_{\rho *} \cong MU_{2*}. In this paper, we blend these stories. We utilize the C2C_2-global spectrum MR\mathbf{MR} defined by Schwede in an unpublished note, which gives rise to a genuine GG-spectrum MRηM \mathbb{R}_\eta for each augmented compact Lie groups η:GC2\eta: G\to C_2, simultaneously generalizing MUGMU_G and MRM \mathbb{R}. In the case of semi-direct product augmentations GC2C2G \rtimes C_2\to C_2 with GG compact abelian Lie and C2C_2 acting by inversion, we show that the restriction along the inclusion GGC2G \subset G \rtimes C_2 is a split surjection MRρGC2MU2GM \mathbb{R}^{G \rtimes C_2}_{\rho *} \rightarrow MU^{G}_{2*}. Additionally, we propose an evenness conjecture, which implies that this map is an isomorphism. Along the way, we define Real η\eta-orientations, Real global orientations, and corresponding notions of equivariant and global group laws.

Keywords

Cite

@article{arxiv.2501.05469,
  title  = {Real Global Group Laws and Hu-Kriz Maps},
  author = {Jack Carlisle and Noah Wisdom and Guoqi Yan},
  journal= {arXiv preprint arXiv:2501.05469},
  year   = {2025}
}

Comments

47 pages, comments welcome!