Math Forum - Ask Dr. Math

Math Forum - Ask Dr. Math

inf means "infimum," or "greatest lower bound."  This is  slightly different from minimum in that the greatest lower bound is  defined as:  x is the infimum of the set S [in symbols, x = inf (S)] iff:  a) x is less than or equal to all elements of S b) there is no other number larger than x which is less than or equal    to all elements of S.  Basically, (a) means that x is a lower bound of S, and (b) means that  x is greater than all other lower bounds of S.