Groups lying between Steinberg groups over non-perfect fields of characteristics 2 and 3
We describe groups lying between Steinberg groups of type ${}^2A_l$, ${}^2D_l$, ${}^2E_6$, or ${}^3D_4$ over different fields of characteristics 2 and 3 in the case where the larger field is an algebraic extension of the smaller non-perfect field.