English

Spectral Homotopy and the Spectral Fundamental Group

Algebraic Topology 2026-03-27 v1 Commutative Algebra

Abstract

In this paper, we introduce an algebraic-topological invariant for commutative pm-rings, termed the spectral fundamental group, which is denoted by πkalg(A)\pi_{k}^{alg}(A). This group is defined via homotopy classes of loops within the space of induced spectral maps, which are generated by the kk-algebra endomorphism monoid of the ring. We establish foundational properties of this invariant, proving that πkalg(A)\pi_{k}^{alg}(A) is an abelian group that naturally respects direct products and admits natural morphisms with respect to fully invariant subrings. Further, we establish an explicit isomorphism between the spectral fundamental group of certain continuous function rings and the classical fundamental group of their associated topological mapping spaces. Finally, utilizing a generalized dual number construction, we present an explicit example of a pm-ring that cannot be embedded into any function ring over a field of characteristic zero, yet possesses a nontrivial spectral fundamental group. This demonstrates that πkalg(A)\pi_{k}^{alg}(A) captures homotopical dynamics that are intrinsically algebraic.

Keywords

Cite

@article{arxiv.2603.25701,
  title  = {Spectral Homotopy and the Spectral Fundamental Group},
  author = {Biswajit Mitra and Sourav Koner},
  journal= {arXiv preprint arXiv:2603.25701},
  year   = {2026}
}