Rational curves on algebraic varieties

A working seminar organized by Raymond Cheng and Stefan Schreieder during the fall of 2024

Rational curves, whether through their abundance or absence, provide a powerful method of measuring the complexity of algebraic varieties.

This seminar falls into three parts. In the first third, we work through the basic theory around rational curves in algebraic varieties and rational connectedness. In the second part, we look to understand recent work of Kollár and Zhiyu Tian on lifting algebraic equivalence of \(1\)-cycles to deformation equivalence, and its arithmetic consequences. The final part of the seminar will cover topics of interest proposed by participants of the seminar.

References

Two excellent and comprehensive references for the basic theory of rational curves on algebraic varieties include the following two books:

These works have been remixed into brief and introductory notes:

Original papers in this subject that we touch upon include:

In the second part of the seminar, we look to understand the recent work of Kollár and Zhiyu Tian:

Schedule

We meet Thursdays in F107 between 14:15 and 15:45. A program may also be found here.

17.10
Stefan Schreieder
Introduction and organization
24.10
Sophie Friesen
Deforming parameterized curves and bend-and-break
07.11
Simon Pietig
Free and very free curves
14.11
Robin Lahni
Smoothing trees, combs, and chains
28.11
Pascal Fong
Constructing sections
05.12
Fumiaki Suzuki
Lifting algebraic to deformation equivalence, I
12.12
Dominique Mattei
Lifting algebraic to deformation equivalence, II
19.12
Raymond Cheng
Geometric Manin Conjecture
16.01
Tim Gräfnitz
Stable curves and stable maps
23.01
Anneloes Viergever
Counting (real) rational curves