∫ ⊂ ⊃ ∫ S C → ⋅ d S → = ∫ ∫ ∫ V ρ d τ {\displaystyle \int \!\!\!\!\!\!\!\subset \!\!\!\supset \!\!\!\!\!\!\!\int _{S}{\vec {C}}\cdot d{\vec {S}}=\int \!\!\!\!\!\int \!\!\!\!\!\int _{V}\rho d\tau ~}
si
d i v C → = ρ {\displaystyle \mathrm {div} \ {\vec {C}}=\rho ~}
