Third-person singular simple present indicative form of deesterify

Information acquired by direct observation rather than by inference.

(mathematics, complex analysis, always plural) Given a complex-valued function f and real-valued functions u and v such that f(z) = u(z) + iv(z), either of the equations (∂u)/(∂x)=(∂v)/(∂y) or (∂u)...

A surname.