Date/heure
11 juin 2018
14:00 - 15:00
Oratrice ou orateur
Marc Soret
Catégorie d'évènement Séminaire de géométrie différentielle
Résumé
We consider a surface S generically immersed in the 4-ball B_4 and bounded by a transverse link L in S_3. Under some conditions at the boundary, we express the self-linking number sl(L) (w.r.t. the contact structure) as
sl(L) = −χ(S) + 2D_S + wind_+
where χ denotes the Euler characteristic, D_S is the number of crossing points and wind_+ counts the tangent planes to S which are Lagrangian and J-complex for some complex structure J on R^4.
We will sketch the proof, discuss the case when the condition at the boundary is not satisfied, give examples and look at the relevance of the formula for minimal surfaces.