ABSTRACT
Note further that the common practice with the infinite-time models was to describe the various 'long-term' models as 'finite-time', so distinguishing them from the 'normal' infinite-time version.
(e) Validity of models. F ina l ly , let us recall the we l l -known fact
that models, inc lud ing the advanced ones which w i l l be out l ined i n
later chapters of this book, are only an ideal izat ion of the real wor ld .
A s well as the methods of mathematical statistics, c o m m o n sense is
