$C_3$-equivariant stable stems
Yueshi Hou, Shangjie Zhang
TL;DR
This work delivers the first detailed computation of the 3-primary spoke-graded C3-equivariant stable stems π^{C3}_{i,j} for i ≤ 25 and −16 ≤ j ≤ 16, introducing spoke-grading to capture RO(C3)-graded phenomena and the additional fixed-point structure. The authors develop a stratified strategy combining isotropy separation, the AHSS for BC3 and its BΣ3/X subquotients, and 3-primary Mahowald invariants to assemble π^{C3}_{i,j} from classical 3-primary data, with careful attention to differentials, extensions, and a_Yright-actions. They establish explicit identifications for i<0, relate π^{C3} to π^{cl}(BC3)^ op and to π^{cl} via Φ^{C3} and Res, and provide extensive charts and tables capturing the 3-primary landscape of the C3-stem problem. The results lay groundwork for extending C3-equivariant calculations to broader ranges and offer a framework for integrating Tate-type spectral sequences and Borel deformations in odd-prime equivariant contexts, with potential implications for higher-order Tate spectral sequences and mixed-prime group computations.
Abstract
We compute the spoke-graded $C_3$-equivariant stable homotopy groups of spheres $π_{i, j}^{C_3}$, for stems less than 25 (i.e. $i\leq 25$) and for weights between -16 and 16 (i.e. $-16\leq j\leq 16$). In particular, for $j=2k$, this corresponds to the usual $RO(C_3)$-graded homotopy groups of spheres $π^{C_3}_{i-j+kλ}$ for some fixed 2-dimensional $C_3$-faithful representation $λ$. We also describe the geometric fixed point map $Φ^{C_3}: π_{i, j}^{C_3}\to π_{i-j}^{cl}$ and the underlying map $Res: π_{i, j}^{C_3}\to π_{i}^{cl}$.
