Operation For a given vector v=(v1,v2,…) For multi-index (x1,x2,…) ∂v∂=[∂v1∂]x1[∂v2∂]x2… Example For vector v=(x,y,z) For multi-index (1,0,2) ∂v∂=[∂x∂]1[∂y∂]0[∂z∂]2=∂x∂z2∂3