14. Jan 2021

An arithmetic count of rational plane curves

ALGEBRAIC GEOMETRY AND NUMBER THEORY SEMINAR

Datum: 14. Januar 2021 | 15:00 – 16:00
Sprecher: Kirsten Wickelgren, Duke University, North Carolina
Veranstaltungsort: https://mathseminars.org/seminar/AGNTISTA

There are finitely many degree d rational plane curves passing through 3d-1 points, and over the complex numbers, this number is independent of (generically) chosen points. For example, there are 12 degree 3 rational curves through 8 points, one conic passing through 5, and one line passing through 2. Over the real numbers, one can obtain a fixed number by weighting real rational curves by their Welschinger invariant, and work of Solomon identifies this invariant with a local degree. It is a feature of A1-homotopy theory that analogous real and complex results can indicate the presence of a common generalization, valid over a general field. We develop and compute an A1-degree, following Morel, of the evaluation map on Kontsevich moduli space to obtain an arithmetic count of rational plane curves, which is valid for any field k of characteristic not 2 or 3. This shows independence of the count on the choice of generically chosen points with fixed residue fields, strengthening a count of Marc Levine. This is joint work with Jesse Kass, Marc Levine, and Jake Solomon.
 

Weitere Informationen:

Datum:
14. Januar 2021
15:00 – 16:00

Sprecher:
Kirsten Wickelgren, Duke University, North Carolina

Veranstaltungsort:
https://mathseminars.org/seminar/AGNTISTA

Ansprechpartner:

Oosthuizen-Noczil Birgit

Email:
birgit.oosthuizen-noczil@ist.ac.at

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