“…About realization of Reeb graphs, there have been a lot of studies, e.g. by Sharko [29], Martínez-Alfaro, Meza-Sarmiento and Oliveira [18,19,20], Masumoto and Saeki [21], Gelbukh [2,3,4,5], Kaluba, Marzantowicz and Silva [12], Michalak [22,23], Michalak and Marzantowicz [17], Kitazawa [13,14,15], etc. Our theorems generalize some of them.…”