On terminal forms for topological polynomials for ribbon graphs: The NN-petal flower

The Bollobas–Riordan polynomial [B. Bollobas, O. Riordan, A polynomial of graphs on surfaces, Math. Ann. 323 (2002) 81–96] extends the Tutte polynomial and its contraction/deletion rule for ordinary graphs to ribbon graphs. Given a ribbon graph GG, the related polynomial should be computable from the knowledge of the terminal forms of GG namely specific induced graphs for which the contraction/deletion procedure becomes more involved. We consider some classes of terminal forms as rosette ribbon graphs with N≥1N≥1 petals and solve their associate Bollobas–Riordan polynomial. This work therefore enlarges the list of terminal forms for ribbon graphs for which the Bollobas–Riordan polynomial could be directly deduced.