Twisted-trace conjecture for Stark elements in abelian towers

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Let L/K/kL/K/k be a tower of abelian extensions with groups G=Gal⁡(L/k)G=\operatorname{Gal}(L/k), H=Gal⁡(L/K)H=\operatorname{Gal}(L/K), and Γ=Gal⁡(K/k)\Gamma=\operatorname{Gal}(K/k). Let SS, TT, S′S', and S”S” be as in the source, with r=∣S′∣r=|S'| and s=∣S”∣−∣S′∣s=|S”|-|S'|. Assume that the Stark conjectures St(L/k,S,T,S′)\mathrm{St}(L/k,S,T,S') and St(K/k,S,T,S”)\mathrm{St}(K/k,S,T,S”) hold. Let Tw⁡L/K(m)=∑h∈Hmh⊗h−1\operatorname{Tw}_{L/K}(m)=\sum_{h\in H}m^h\otimes h^{-1} be the twisted trace and let AH\mathcal{A}_H be the augmentation ideal of Z[H]\mathbb{Z}[H].

Twisted-trace conjecture. The following two assertions hold:

  1. Tw⁡L/K(ϵL)∈(⋀rUL)⊗G⋀rWL,S′∗⊗ZAHs\operatorname{Tw}_{L/K}(\epsilon_L)\in\bigl(\bigwedge^rU_L\bigr)\otimes_G\bigwedge^rW^*_{L,S'}\otimes_{\mathbb{Z}}\mathcal{A}_H^s;
  2. modulo AHs+1\mathcal{A}_H^{s+1},
Tw⁡L/K(ϵL)≡(jL/K⊗1)(RL/KArt(ϵK))\operatorname{Tw}_{L/K}(\epsilon_L)\equiv(\mathbf{j}_{L/K}\otimes1)\bigl(\mathcal{R}^{\mathrm{Art}}_{L/K}(\epsilon_K)\bigr)

in (⋀rUL)⊗G⋀rWL,S′∗⊗ZAHs/AHs+1\bigl(\bigwedge^rU_L\bigr)\otimes_G\bigwedge^rW^*_{L,S'}\otimes_{\mathbb{Z}}\mathcal{A}_H^s/\mathcal{A}_H^{s+1}. The conjecture relates leading terms in the equivariant class-number formula across an abelian tower and predicts both the order of vanishing and its leading coefficient. No resolution is supplied in the source or parser evidence.

References

Primary source

Barry Mazur and Karl Rubin, “Refined class number formulas for G_m”, arXiv:1312.4053 (2013).

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