English

Associative Schemes

Algebraic Geometry 2024-10-23 v4

Abstract

We state results from noncommutative deformation theory of modules over an associative kk-algebra A,A, kk a field, necessary for this work. We define a set of AA-modules aSpecA\operatorname{aSpec}A containing the simple modules, whose elements we call spectral, for which there exists a topology where the simple modules are the closed points. Applying results from deformation theory we prove that there exists a sheaf of associative rings OX\mathcal O_X on the topological space X=aSpecAX=\operatorname{aSpec}A giving it the structure of a pointed ringed space. In general, an associative variety XX is a ringed space with an open covering {Ui=aSpecAi}iI.\{U_i=\operatorname{aSpec}{A_i}\}_{i\in I}. When AA is a commutative kk-algebra, aSpecA\specA,\operatorname{aSpec}A\simeq\spec A, and so the category \cataVark\cat{aVar}_k of associative varieties is an extension of the category of varieties \catVark,\cat{Var}_k, i.e. there exists a faithfully full functor I:\catVark\cataVark.I:\cat{Var}_k\rightarrow\cat{aVar}_k. Our main result says that any associative variety XX is aSpec(OX(X))\operatorname{aSpec}(\mathcal O_X(X)) for the kk-algebra OX(X),\mathcal O_X(X), and so any study of varieties can be reduced to the study of the associative algebra OX(X).\mathcal O_X(X).

Keywords

Cite

@article{arxiv.2302.13843,
  title  = {Associative Schemes},
  author = {Arvid Siqveland},
  journal= {arXiv preprint arXiv:2302.13843},
  year   = {2024}
}
R2 v1 2026-06-28T08:50:38.679Z