A function 
is said to have a lower bound 
if 
for all 
in its domain. The greatest
lower bound is called the infimum.
Lower Bound
See also
Inequality, Infimum, Supremum, Upper BoundPortions of this entry contributed by Todd Rowland
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Cite this as:
Rowland, Todd and Weisstein, Eric W. "Lower Bound." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/LowerBound.html