Document Type : Full Length Article

**Author**

Department of Science, Islamic Azad University, Savadkooh Branch, Savadkooh, Mazandaran, I. R. Iran

**Abstract**

Let G be a simple connected graph. The vertex PI polynomial of G is defined as PI_{v}(G ,x )=Σ_{e=uv} X^{nu(e)+nv(e) }here n_{u}(e) is the number of vertices closer to u than v and n_{v}(e) is the number of vertices closer to v than u. The PI polynomial of G is defined as PI(G ,x )=Σ_{e=uv} X^{mu(e)+mv(e)} , where m_{u}(e) is the number of edges closer to u than v and m_{v}(e) is the number of edges closer to v than u. In this paper, the PI and vertex PI polynomials of two types of dendrimers are computed.

**Graphical Abstract**

**Keywords**

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June 2011

Pages 59-65

**Receive Date:**03 January 2011**Revise Date:**06 February 2011**Accept Date:**15 March 2011**Publish Date:**01 June 2011