Regular Circle Actions on 2-connected 7-manifolds

TL;DR

This paper classifies 2-connected 7-manifolds that admit regular circle actions, providing a complete understanding of their topological and smooth structures.

Contribution

It uniquely determines the homeomorphism and diffeomorphism types of such manifolds admitting regular circle actions.

Findings

Complete classification of 2-connected 7-manifolds with circle actions

Identification of topological types of these manifolds

Determination of smooth structures compatible with circle actions

Abstract

We determine the homeomorphism (resp. diffeomorphism) types of those 2-connected 7-manifolds (resp. smooth 2-connected 7-manifolds) that admit regular circle actions (resp. smooth regular circle actions).