This problem considers a continuous time Markov chain model

This problem considers a continuous time Markov chain model for the chang­ing pattern of relationships among members in a group. The group has four members: a, b, c, and d. Each pair of the group may or may not have a certain relationship with each other. If they have the relationship, we say that they are linked. For example, being linked may mean that the two members are commu­nicating with each other. The following graph illustrates links between a and b, between a and c, and between b and d:

Solution

given links are,

a and b are linked that means a and b are communicating

a and c are linked that means a and c are communicating

b and d are linked that means b and d are communicating

by class property if a is communicating with b, and b is communicating with d then a also communicate with d

vide, d communicaing with c.

hence above graph shows the {a b c d} all are communicating