In mathematics, an ancient solution to a differential equation is a solution that can be extrapolated backwards to all past times, without singularities.
That is, it is a solution "that is defined on a time interval of the form (−∞, T).
"[1] The term was introduced by Richard Hamilton in his work on the Ricci flow.
[2] It has since been applied to other geometric flows[3][4][5][6] as well as to other systems such as the Navier–Stokes equations[7][8] and heat equation.
This mathematical analysis–related article is a stub.