The smallest 
for which a point 
is a periodic point of a function 
so that 
. For example, for the function 
, all points 
have period 2 (including 
). However, 
has a least period of 1. The analogous concept exists
for a periodic sequence, but not for a periodic
function. The least period is also called the exact period.
Least Period
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Cite this as:
Weisstein, Eric W. "Least Period." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/LeastPeriod.html