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

Understand

The Bollobas-Riordan polynomial [Math.

• Ann.
• 323, 81 (2002)] extends the Tutte polynomial and its contraction/deletion rule for ordinary graphs to ribbon graphs.
• Given a ribbon graph $\cG$, the related polynomial should be computable from the knowledge of the terminal forms of $\cG$ namely specific induced graphs for which the contraction/deletion procedure becomes more involved.