|Definition:|| quantity representing the quantities in a finite set or in an interval,|
- for n quantities , by the reciprocal of the mean value of their reciprocals:
if none of the n quantities is equal to zero;
if at least one quantity is equal to zero;
- for a quantity x depending on a variable t, by the quantity defined by the reciprocal of the mean value of the reciprocal of the given quantity:
if the value of the integral is finite;
in other cases
Note 1 to entry: The harmonic mean value of a periodic quantity is usually taken over an integration interval the range of which is the period multiplied by a natural number.
Note 2 to entry: The harmonic mean value of a quantity is denoted by adding the subscript h to the symbol of the quantity.