Linked from
The 56 pages that link to Partial differential equation, each with the reason it gives.
Heat equationNarrower topic: The heat equation is a canonical example of this broad equation class.
Wave equationNarrower topic: The wave equation belongs to this broad class of equations.
Poisson's equationNarrower topic: Poisson's equation belongs to this broad family of equations.
Joseph FourierNarrower topic: The heat equation that motivated Fourier’s work belongs to this class.