Free Product Structure of a Graph W*-probability space
  In this paper, we observe the amalgamated free product structure of a Graph W*-probability space. In [16] and [17], we already observed the operator-valued freeness conditions on a graph W*-algebra. By using the conditions, we will consider the amalgamated free product structure of a graph W*-algebra. In particular, we can make the algebra be blocked, by so-called the loop free blocks (D_G-semicircular blocks) and non-loop blocks (R-diagonal blocks). Finally, we can see the the graph W*-algebra is the free product of edge blocks of the algebra. 
Ilwoo Cho