The theorem on planar graphs (Q1071005)

In 1930 \textit{K. Kuratowski} published a proof of the ''Theorem on planar graphs'': A graph is planar if and only if it does not contain a subgraph homeomorphic to either \(K_ 5\) (the complete graph on 5 points), or \(K_{3,3}\) (the complete bipartite graph on 3,3 points). The authors tell the history of the discovery of the theorem and its proof, in which other mathematicians like O. Frink, P. A. Smith, L. S. Pontrjagin and K. Menger are involved. The authors clarify to what extent the attachment of Pontrjagin's name to this theorem is justified.