wˌɛɹ dᵻnˈoʊts ðə nˈæblə ˈɑːpɚɹˌeɪɾɚ wɪð ɹᵻspˈɛkt tʊ ˈɛks, ænd ðɪ ˈɑːpɚɹˌeɪɾɚ jˈuː ɪz təbi ɐplˈaɪd tʊ ˈiːtʃ kəmpˈoʊnənt ʌv ˈɛf.
where ∇ denotes the nabla operator with respect to x, and the operator u⋅∇ is to be applied to each component of F.