ON DEHN'S LEMMA AND THE ASPHERICITY OF KNOTS

1957/01/15 by C. D. Papakyriakopoulos · 3 citations
Mathematics · #Geometric and Algebraic Topology #Homotopy and Cohomology in Algebraic Topology #Algebraic Geometry and Number Theory #Lemma (botany) #Combinatorics #Mathematics #Biology #Botany

paper · doi:10.1073/pnas.43.1.169

openalex publication_date 1957/01/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/30

Abstract

Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.

Cited by

• The Embedding of Two-Spheres in the Four-Sphere
• On proper branched coverings and a question of Vuorinen
• 3-manifold [wikipedia]