The document defines and provides properties of gradient, divergence, and curl - three important vector operators in multi-variable calculus. Gradient is defined as the maximum rate of change of a scalar function in space. Divergence measures how a vector field spreads out from a point, with zero divergence indicating a solenoidal (non-spreading) field. Curl measures the maximum rotation of a vector field around a point, with zero curl indicating an irrotational (non-rotating) field. Stokes' theorem relates the circulation of a vector field around a closed path to the surface integral of the curl over the enclosed surface.