Remarks on E11 approach

We consider a few topics in E-11 approach to superstrings/M-theory: even subgroups (Z(2) orbifolds) of E-n, n = 11, 10, 9 and their connection to Kac-Moody algebras, particularly to EE11 subgroup of E-11; possible form of supersymmetry relation in E-11; decomposition of first fundamental representation l(1) w.r.t. the SO(10, 10) and its square-root at first few levels; particle orbit of l(1) x E-11. Possible relevance of coadjoint orbits method is noticed, based on a self-duality form of equations of motion in E-11.