# Time reversal symmetry

• For wave equations, the time-reversal of a solution ${\displaystyle u(t,x)}$ is usually ${\displaystyle u(-t,x)}$, although for tensor-valued fields one may also have to negate certain "time components" of the field.
• For Schrodinger equations, the time-reversal of a solution ${\displaystyle u(t,x)}$ is usually ${\displaystyle {\overline {u}}(-t,x)}$.
• For KdV-type equations and the Benjamin-Ono equation, the time-reversal of a solution ${\displaystyle u(t,x)}$ is usually ${\displaystyle u(-t,-x)}$.