Seminar for Geometry, education and visualization with applications
PROGRAM
MATEMATIČKI INSTITUT SANU
Seminar geometriju, obrazovanje i vizualizaciju sa primenama
PLAN RADA ZA OKTOBAR 2021.
ČETVRTAK, 21.10.2021. u 16:20, On-line
Jelena Stanković, Učiteljski fakultet, Beograd
NONLOCAL DE SITTER GRAVITY AND ITS COSMOLOGY
General relativity (GR), i.e. Einstein theory of gravity, is recognized as one of the best physical theories -- with nice theoretical properties and significant phenomenological confirmations. Nevertheless, GR is not a complete theory of gravity and there are many attempts to modify it. One of the actual approaches towards more complete theory is nonlocal modified gravity. Nonlocal gravity model, which we consider here without matter, is given by the action, where R is scalar curvature and Λ --cosmological constant. Derivation of equations of motion is presented in [1]. We plan to present a brief review of general properties, and then discuss exact cosmological solutions.
One of the exact cosmological solutions mimics the dark matter and the dark energy, see [2]. Computed cosmological parameters are in a good agreement with standard model of cosmology.
[1] I. Dimitrijevic, B. Dragovich, Z. Rakic and J. Stankovic,
Variations of infinite derivative modified gravity, Springer Proc. Math. Stat.
263 (2018), 91-111.
[2] I. Dimitrijevic, B. Dragovich, A.S. Koshelev, Z. Rakic and J. Stankovic,
Cosmological solutions of a nonlocal square root gravity, Phys. Lett. B
797 (2019), 134848.
Kompletan apstrakt, kao i informaciju o ostalim predavanjima na naučnom skupu "2nd Conference on Nonlinearity" možete naći na sajtu https://www.nonlinearity2021.matf.bg.ac.rs.
ČETVRTAK, 28.10.2021. u 17:00, On-line
Vladica Andrejić, Matematički fakultet, Beograd
O OSERMANOVOJ HIPOTEZI
Osermanova hipoteza je pitanje da li je svaka Osermanova mnogostrukost lokalno dve-tačke homogena. Objasnićemo zašto je ova hipoteza važna stvar u Rimanovoj geometriji, te dati osvrt na ono što se do sada zna. Nakon toga predstavljamo najnovije (još uvek neobjavljene) rezultate koji bi u bliskoj budućnosti mogli da doprinesu rešavanju pojedinih slučajeva hipoteze, a baziraju se nan uspostavljanju Principa proporcionalnosti čiji je Princip dualnosti specijalni slučaj.
Sednice seminara odrzavaju se u zgradi Matematickog instituta SANU, Knez Mihailova 36, na trecem spratu u sali 301f.
Rukovodilac Seminara dr Stana Nikcevic
