  This work is devoted to study the relation between regularity and decay for
solutions of the two-dimensional modified Zakharov-Kuznetsov equation in the
weighted Sobolev spaces $Z_{s,(r_1,r_2)}:=H^s(\R^2)\cap
L^2((1+|x|^{2r_1}+|y|^{2r_2})dxdy)$.
