''Persistence'' also means how long a CRT 's Phosphor s glow, or remain lit, after they have been struck by electrons from the CRT's Electron Gun . Older computer monitors ("green screens") had a long persistence, leading to a visual effect called ''ghosting''.
In mathematics, the additive or multiplicative Persistence Of A Number is how often one has to replace that number with the sum or product of its digits until one arrives at a single digit.
