In this paper‎, ‎by studying three $q$-Catalan identities given by Andrews‎, ‎we arrive at a certain number of congruences‎. ‎These congruences are all modulo $Phi_n(q)$‎, ‎the $n$-th cyclotomic polynomial or the related ...

‎In this paper‎, ‎we initially introduce the concept of $n$-distance-balanced property which is considered as the generalized concept of distance-balanced property‎. ‎In our consideration‎, ‎we also define the new concept ...

The vertex PI index $PI(G) = sum_{xy in E(G)} [n_{xy}(x)‎ + ‎n_{xy}(y)]$ is a distance-based molecular structure descriptor‎, ‎where $n_{xy}(x)$ denotes the number of vertices which are closer to the vertex $x$ than to the ...

Let $R$ be a commutative ring with unity. The comaximal ideal graph of $R$, denoted by $mathcal{C}(R)$, is a graph whose vertices are the proper ideals of $R$ which are not contained in the Jacobson radical of $R$, and two ...