Petak, 03. decembar 2004. u 12h, sala 2 MI SANU BG:

Dragan Stevanovic, Prirodno-matematicki fakultet, Nis
SPEKTRALNA TEORIJA GRAFOVA: PAR ALATA I REZULTATA

Sadrzaj. Dva najpopularnija alata u dokazima u spektralnoj teoriji grafova su, bez sumnje, Rejlijev odnos i teorema o preplitanju. Njihova primena ce biti ilustrovana na nekoliko skorašnjih rezultata predavaca koji se ticu najvece sopstvene vrednosti neregularnih grafova, stabala sa ogranicenim najvecim stepenom cvora itd. Pored toga, bice predstavljeno i nekoliko otvorenih problema.

Petak, 10. decembar 2004. u 11h, sala 2 MI SANU:

Prof. Leo Liberti, DEI, Politecnico di Milano, Italy
SOLVING A QUANTUM CHEMISTRY PROBLEM WITH DETERMINISTIC GLOBAL OPTIMIZATION

Abstract. The Hartree-Fock method is well known in quantum chemistry, and widely used to obtain atomic and molecular eletronic wave functions, based on the minimization of a functional of the energy. This gives rise to a multi-extremal, nonconvex, polynomial optimization problem. We give a mathematical programming formulation of the problem, which we solve by using a spatial Branch-and-Bound algorithm. Lower bounds are obtained by solving a tight linear relaxation of the problem derived from an exact reformulation based on reduction constraints (a subset of RLT constraints). The proposed approach was successfully applied to the ground-state of the He and Be atoms.

Petak, 17. decembar 2004. u 14h, sala 2 MI SANU:

Arpad Takaci, Departman za matematiku i informatiku, PMF, Novi Sad
NELINEARNE OPERATORSKE DIFERENCIJALNE JEDNACINE

Sadrzaj. Posmatraju se nelinearne diferencijalne jednacine u polju operatora Mikusinskog koje odgovaraju parcijalnim integro-diferencijalnim jednacinama sa odgovarajucim uslovima. Primenjuju se metode pribliznog resavanja ovih jednacina pomocu postupaka analognih klasicnim postupcima kao sto su metoda sukcesivnih aproksimacija, Ojlerova i druge metode. Posebno se analiyira karakter tako dobijenih resenja u zavisnosti od tipa jednacine i uslova.

Petak, 24. decembar 2004. u 14h, sala 718, MF BGD:

Dragan S. Djordjevic, Department of Mathematics and Informatics, Faculty of Science and Mathematics, University of Nis
CHARACTERIZATIONS OF NORMAL OPERATORS AND THEIR GENERALIZATIONS INVOLVING PSEUDO INVERSES

Abstract. The class of normal operators on a Hilbert space is characterized involving the Moore-Penrose inverse. Moreover, some generalizations of normal operators are characterized in a similar way. Results are extended to C*-algebra settings.

Petak, 31. decembar 2004. u 14h, sala 2, MI SANU:

SRECNA NOVA GODINA!