English

Revisiting Pontryagin's Proof of Stable Stems 1 and 2

Algebraic Topology 2025-03-17 v1 Geometric Topology

Abstract

In this paper, we introduce fundamental notions of homotopy theory, including homotopy excision and the Freudenthal suspension theorem. We then explore framed cobordism and its connection to stable homotopy groups of spheres through the Pontryagin-Thom construction. Using this framework, we compute the stable stems in dimensions 00, 11, and 22. This work is primarily expository, revisiting proofs from \cite{Pont1} with slight modifications incorporating modern notation. Furthermore, in the final section, we discuss 2-dimensional framed manifolds with Arf invariant one and examine why the result of \cite{Pont2} regarding π2S\pi_2^S is incorrect.

Keywords

Cite

@article{arxiv.2503.11211,
  title  = {Revisiting Pontryagin's Proof of Stable Stems 1 and 2},
  author = {Trishan Mondal},
  journal= {arXiv preprint arXiv:2503.11211},
  year   = {2025}
}

Comments

24 pages, 8 figures