فهرست نشریات علمی دسترسی آزاد ایران

‎Let $G=(V,E)$ be a simple graph‎. A function $f:V\rightarrow \mathbb{N}\cup \{0\}$ is called a configuration of pebbles on the vertices of $G$ and the quantity $\vert f\vert=\sum_{u\in V}f(u)$‎ ‎is called the weight of $f$ which is just the total number of pebbles assigned to vertices‎. ‎A pebbling step from a vertex $u$ to one of its‎ neighbors $v$ reduces $f(u)$ by two and increases $f(v)$ by one‎. ‎A pebbling configuration $f$ is said to be solvable if for every vertex $ v $‎, ‎there exists a sequence (possibly empty) of pebbling moves that results in a pebble on $v$‎. ‎The pebbling number $ \pi(G) $ equals the minimum number $ k $ such that every pebbling configuration $ f $ with $ \vert f\vert = k $ is solvable‎. Let $ G $ be a connected graph constructed from pairwise disjoint connected graphs $ G_1,...,G_k $ by selecting a vertex of $ G_1 $‎, ‎a vertex of $ G_2 $‎, ‎and identifying these two vertices‎. ‎Then continue in this manner inductively‎. ‎We say that $ G $ is a polymer graph‎, ‎obtained by point-attaching from monomer units $ G_1,...,G_k $‎. In this paper‎, ‎we study the pebbling number of some polymers‎. ‎