A First Course in String Theory

14.1 Counting bosonic states

12.11 Counting symmetric products

~~~

is the number of ‘s.

is the number of different ‘s.

For and , one of the possible configurations is

The problem is equivalent to that of assigning balls to boxes.

Box 1 collects the ‘s with index 1.

Box 2 collects the ‘s with index 2.

…

— Me@2015-07-13 03:34:32 PM

2015.07.14 Tuesday (c) All rights reserved by ACHK