Petrovsky lacuna
Encyclopedia
Hyperbolic partial differential equation
In mathematics, a hyperbolic partial differential equation of order n is a partial differential equation that, roughly speaking, has a well-posed initial value problem for the first n−1 derivatives. More precisely, the Cauchy problem can be locally solved for arbitrary initial data along...
vanishes.
They were studied by who found topological conditions for their existence.
Petrovsky's work was generalized and updated by .