{{math|''X''<sub>1</sub>, ... , ''X''<sub>''N''</sub>}} are quadratic and independent degrees of freedom if the energy associated with a microstate of the system they represent can be written as:
{{math|''X''<sub>1</sub>, ... , ''X''<sub>''N''</sub>}} are quadratic and independent degrees of freedom if the energy associated with a microstate of the system they represent can be written as:
−
are quadratic and independent degrees of freedom if the energy associated with a microstate of the system they represent can be written as:
+
{{math|''X''<sub>1</sub>, ... , ''X''<sub>''N''</sub>}} are quadratic and independent degrees of freedom if the energy associated with a microstate of the system they represent can be written as: