  Capillary condensation, which takes place in confined geometries, is the
first-order vapor-to-liquid phase transition and is explained by the Kelvin
equation, but the equations applicability for arbitrarily curved surface has
been long debated and is a sever problem. Recently, we have proposed generic
dynamic equations for moving surfaces. Application of the equations to static
shapes and modelling the pressure at the interface nearly trivially solves the
generalization problem for the Kelvin equation. The equations are universally
true for any surfaces: atomic, molecular, micro or macro scale, real or
virtual, Riemannian or pseudo-Riemannian, active or passive.
