而家有M粒distinguishable particles, 要分去三個state, 有幾多種分法
我都知好on9, 但係我唔明究竟呢兩種計法點解會出唔同既答案
1. 因為係將M個particle放係三個state, 我可以當成有M balls + 2 sticks, 於是總分法有 (M+2)!/2!1!1!...1! = (M+2)!/2 (multinomial)
2. 每粒particle都有三種分法, 逐粒逐粒放去d states到, 總共有3^M種分法