  Gradually Truncated Log-normal distribution - Size distribution of firms
  Abstract
  Many natural and economical phenomena are described through power law or log-
normal distributions. In these cases, probability decreases very slowly with
step size compared to normal distribution. Thus it is essential to cut-off
these distributions for larger step size. Recently we introduce the gradually
truncated power law distribution to successfully describe variation of
financial, educational, physical and citation index. In the present work, we
introduce gradually truncated log-normal distribution in which we gradually
cut- off larger steps due to physical limitation of the system. We applied this
distribution successfully to size distribution of USA.\'{}s manufactoring firms
which is measured through their annual sell. The physical limitation are due to
limited market size or shortage of highly competent executives.
