div x u div x u div x y u div x y u operatorname ⋆-lim'sup x → 0 u ⋆-lim'sup w u ⋆-lim'sup x → 0 w u ⋆-lim'sup x → 0 w u operatorname* ⋆-lim'sup x → 0 u ⋆-lim'sup w u ⋆-lim'sup x → 0 w u ⋆-lim'sup x → 0 w u operatorname*:nolimits curl x v argmax K u DeclareMathOperator