can someone explain what all the letters mean in this equation (optimal portfolio weights)

[E(r,)-r,]o-[E(r,)-r,]0,0sP8s BS WB %3D RS [E(r,)-r, ]o, +[E(;)-r, ]o, -[E(",)r, + E(r,)r,]o,0 sPs [E(r,)-r, Jo-[E(r.)-r, ]0,0;P85 [E(r,)-r,lo +[E(r,)-r,]o,-[E(r,)-r, + E(r,)-r, ]o,0 sPs WB Ws =1-wg