Orateur: Peter Feller (ETH Zürich)
Titre: Knot theory and embedding questions in complex geometry.
Résumé: Eyecatcher: Drawing non-trivial knots is hard. This can be made precise by a simple argument, which in turn, surprisingly, yields non-trivial results in complex algebraic geometry.

Details: Knots---embeddings of the circle in R^3---naturally arise in the study of 3-manifolds and 4-manifolds. We will discuss how a naive idea from knot theory---the 'drawing nontrivial knots is hard'-principle---yields results in the context of embeddings of the complex line C in C^n and complex matrix groups. The notions of knot concordance and the slice genus make an appearance and are used to establish a classical algebraic embedding result.

It is almost Christmas: no knowledge about knots, algebraic geometry, or complex geometry will be assumed.

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