Let G be a group and R,L,S be subsets of G such that $R=R^{-1}$, $L=L^{-1}$ and $1\notin R\cup L$. The undirected graph $\SC(G;R,L,S)$ with vertex set  union of $G_1=\{g_1\mid g\in G\}$ and $G_2=\{g_2\mid g\in G\}$, and ...

We present a new and simple direct approach based on generalized moving least squares (GMLS) for computing the first derivatives of the functions defined on the sphere. The novel method utilizes a Householder transformation ...

The Hosoya index $Z(G)$ of a graph $G$ is the total number of matchings in it. In this paper, the recursive formulas of the Hosoya index of semitotal graph $Q(G)$ and total graph $T(G)$ for certain graphs $G$ are obtained. ...

Ali Reza Ashrafi (10 May 1964 9 January 2023) was an Iranian mathematician who worked in computational group theory and mathematical chemistry. Ashrafi was a professor at the Department of Pure Mathematics of the University ...

Ali Reza was my friend. I firmly believe that this friendship was mutual. In my long academic career, I had scientific cooperation with numerous colleagues (more than 800), but very few of them where my friends. Somewhere ...