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A rigidity theorem for π*-étale 𝔼k-algebras
Abstract
We prove a rigidity theorem for π*-étale 𝔼k-algebras over an 𝔼k+1-ring spectrum: the category of π*-étale extensions of an 𝔼k-algebra is identified with the ordinary category of étale Dirac algebras over its graded homotopy Dirac ring. The proof develops a relative Goerss-Hopkins type obstruction theory in synthetic spectra, including an I-complete version. As an application, the completed obstruction theory constructs the In-complete 𝔼3-MU(p)-algebra realization of the Lubin-Tate theory, hence an 𝔼4-orientation MU(p)→ En.
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BibTeX
@misc{li2026rigidity,
title = {{A rigidity theorem for $π_*$-étale $\mathbb E_k$-algebras}},
author = {Xiansheng Li},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2607.22680},
eprint = {2607.22680},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.22680},
}
RIS
TY - UNPB
TI - A rigidity theorem for π_*-étale 𝔼_k-algebras
AU - Xiansheng Li
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2607.22680
UR - https://arxiv.org/abs/2607.22680
AB - We prove a rigidity theorem for π_*-étale 𝔼_k-algebras over an 𝔼_k+1-ring spectrum: the category of π_*-étale extensions of an 𝔼_k-algebra is identified with the ordinary category of étale Dirac algebras over its graded homotopy Dirac ring. The proof develops a relative Goerss-Hopkins type obstruction theory in synthetic spectra, including an I-complete version. As an application, the completed obstruction theory constructs the I_n-complete 𝔼_3-MU_(p)-algebra realization of the Lubin-Tate theory, hence an 𝔼_4-orientation MU_(p)→ E_n.
ER -