existence and uniqueness of solutions of nonlinear differential equations, spectral theory of linear and nonlinear operators, finding branches of solutions of nonlinear partial differential equations, development of variational methods for studying nonlinear equations, development variational methods for finding critical characteristics of nonlinear models, development of new approaches for finding bifurcations of solutions of nonlinear equations, development of new approaches for the numerical analysis of critical phenomena in nonlinear models , mathematical physics, construction of a generalized Collatz-Wielandt formula and a generalized Rayleigh quotient for nonlinear problems, development of the theory of optimal inverse spectral problems, development of variational methods for studying special classes of solutions, including solutions with compact supports and free boundaries, blow-up solutions, ground states
Main publications:
Ilyasov Y.Sh., “Bifurcation calculus by the extended functional method”, Funct. Anal. Appl., 41:1 (2007), 18–30
Ilyasov Y., “A duality principle corresponding to the parabolic equations”, Physica D, 237:5 (2008), 692–698
Ilyasov Y., “On nonlocal existence results for elliptic equations with convex-concave nonlinearities”, Nonlinear Analysis, 61:1-2 (2005), 211–236
Ilyasov Y., Runst T., “On nonlocal calculation for inhomogeneous indefinite Neumann boundary value problems”, Calculus Var. & Part. Diff. Eq., 22:1 (2005), 101–127
Ilyasov Y., “On positive solutions of indefinite elliptic equations”, C. R. Acad. Sci. Paris S\er. I Math., 333:6 (2001), 533–538
