Let's consider two tuples.
(1,2)
(2,1)
The two tuples are forming a loop right? 1-2-1 .
So for this , you need to do a self join and check for which pair of tuples .
t1.Y = t2.X and t2.Y = t1.X
You can print those tuples.
The relation algebra expression is correct.
If it needs to be written in sql , it would be like ,
Select * from Adjacency A1 , Adjacency A2 on A1.Y = A2.X where A2.Y = A1.X.
Kindly correct me if I went wrong somewhere.
