# Courant–Friedrichs–Lewy condition

It is an important stability criterion for hyperbolic equations.

In common case it's written as

 $C=c\frac{\Delta t}{\Delta x} \leq 1$ (2)

where C is called the Courant number

Courant, R., K. O. Fredrichs, and H. Lewy (1928), "Uber die Differenzengleichungen der Mathematischen Physik", Math. Ann, vol.100, p.32, 1928.