Mironenko reflecting function
In applied mathematics, the reflecting function F ( t , x ) {\displaystyle \,F(t,x)} of a differential system x ˙ = X ( t , x ) {\displaystyle {\dot {x}}=X(t,x)} connects the past state x ( − t ) {\displaystyle \,x(-t)} of the system with the future state x ( t ) {\displaystyle \,x(t)} of the system by the formula x ( − t ) = F ( t , x ( t ) ) . {\displaystyle \,x(-t)=F(t,x(t)).} The concept of the reflecting function was introduced by Uladzimir Ivanavich Mironenka.
Source: Wikipedia — Mironenko reflecting function (CC BY-SA 4.0)