Help what should i do ,about convex*real affine or concave*real affine

q1 is variable l1_0_1 >=(q1-W0).^2 is a constraint
i have already try to change cvx_begin to cvx_begin sdp that can‘t work
and try to use a1>=a to replace a in the formula that can’t work too
why ?

actually the l2_0_1 is also a variable ,we can’t use a variable *variable ,but how to deal with it

Have you proven this is a convex optimization problem? It is somewhat confusing because the error message shows code which you don’t display or talk about.