Vesti

U sredu 21. septembra 2022. godine akademik Stefan Ivanov (Stefan Ivanov), profesor Fakulteta za matematiku i informatiku Univerziteta "Sv. Кliment Ohridski" iz Sofije i Instituta za matematiku i informatiku Bugarske akademije nauka (University of Sofia "St. Kl. Ohridski", Faculty of Mathematics and Informatics, Bulgaria; Institute of Mathematics and Informatics, Bulgarian Academy of Sciences) posetiti Univerzitet u Nišu i Prirodno-matematički fakultet u Nišu.

U okviru posete našem Fakultetu prof. Stefan Ivanov će u sali br. 100 održati predavanje The CR Almost Schur Lemma and the positivity conditions sa početkom u 13.00 sati.

Abstract:

We establish a new version of the CR almost Schur Lemma which gives an estimation of the pseudohermitian scalar curvature on a compact strictly pseudoconvex pseudohermitian manifold to be a constant in terms of the norm of the traceless Webster Ricci tensor and the pseudohermitian torsion  under a certain positivity condition. In the torsion-free case, i.e. for a compact Sasakian manifold, our positivity condition coincides with the known one and we obtain a better estimate.