Nonlocal problems for partial differential equations.
Main publications:
Sergei A. Beilin, “Existence of solutions for one-dimensional wave equations with nonlocal conditions”, Electronic Journal of Differential Equations, 2001, no. 76, 8 p.
Sergei A. Beilin, “On a mixed nonlocal problem for a wave equation”, Electronic Journal of Differential Equations, 2006, no. 103, 10 p.