“…Fractional BVPs defined on intervals have been studied by many authors. Many results on the existence, uniqueness, multiplicity, and nonexistence of solutions for fractional differential equations subject to various boundary conditions (BCs) have been obtained; see for example [1,2,4,7,8,11,12,13,14,15,16,17,19,20,25,26,27]. To the best of our knowledge, no work has been done for fractional BVPs on graphs.…”