Theory of orthogonal series and bases, Theory of weighted functional spaces, Non-linear approximations, greedy algorithms, Wavelets and theory of vector-valued functions, Signal processing.
Main publications:
S.A. Episkoposian, “On the existence of universal series by trigonometric system”, Journal of Functional Analysis, 230 (2006), 169–183
S.A. Episkoposian, “Universal series by trigonometric system in
weighted spaces”, International Journal Mathematics and Mathematical Sciences, 19 (2006), 62909
S.A. Episkoposian, “On the divergence of Greedy algorithms
with respect to Walsh subsystems in $L^1$”, Nonlinear Analysis: Theory, Methods & Applications, 66 (2007), 1782–1787
S.A. Episkoposian, “On greedy algorithms with respect to generalized Walsh system”, Global Journal of Pure and Applied Mathematics, 3 (2007), 77–86
S.A. Episkoposian, “$L^1$-convergence of greedy algorithm by generalized Walsh system”, Banach Journal of Mathematical Analysis, 6:3 (2012), 161–174
