Freedman, Michael H. Working and playing with the 2-disk. (English) Zbl 0924.57026 Browder, Felix E. (ed.), Mathematics into the twenty-first century. Proceedings of the AMS centennial symposium, Providence, RI, USA, August 8–12, 1988. Providence, RI: American Mathematical Society. Am. Math. Soc. Centen. Publ. 2, 37-47 (1992). This article is the written form of a lecture held by the author at the AMS centennial symposium. He recalls classical results of geometric topology in the 20th century, particularly in dimensions 2, 3 and 4.For the entire collection see [Zbl 0921.00016]. MSC: 57N99 Topological manifolds 30C30 Schwarz-Christoffel-type mappings 30C35 General theory of conformal mappings 57M99 General low-dimensional topology 57N35 Embeddings and immersions in topological manifolds 57N45 Flatness and tameness of topological manifolds 57N50 \(S^{n-1}\subset E^n\), Schoenflies problem 57R80 \(h\)- and \(s\)-cobordism 57R65 Surgery and handlebodies 57Q25 Comparison of PL-structures: classification, Hauptvermutung Keywords:embedding; Alexander horned sphere; wild embedding; tame embedding; collar; Schoenflies theorem; surgery; Whitney trick; \(h\)-cobordism; \(S\)-cobordism; Hauptvermutung; exotic spheres PDFBibTeX XMLCite \textit{M. H. Freedman}, Am. Math. Soc. Centen. Publ. 2, 37--47 (1992; Zbl 0924.57026)