The concept of element transition probability and the structure of internal inverse
-set
were proposed based on the inverse P-sets (
,
) and the randomness of element transition. The relationship between internal inverse P-set
and internal inverse
-set
was discussed, which showed
is the general forming of
while
is a special case of
. The relationship theorem between
and element transition probability, and the identification theorem between internal inverse
-set family and internal inverse P-set family were presented. Furthermore analysis of the probability feature about internal inverse
-set
was given at the end.