University of Tehran

output

20022009

most citedCosmological coincidence problem in interacting dark energy models

154 citations

Showing math.COShow all

2 papers · 1 filter

math.CO2007

Inclusion Matrices and Chains

E. Ghorbani, G. B. Khosrovshahi, Ch. Maysoori +1

Given integers $t$ , $k$ , and $v$ such that $0 \leq t \leq k \leq v$ , let $W_{t k} (v)$ be the inclusion matrix of $t$ -subsets vs. $k$ -subsets of a $v$ -set. We modify slightly the concep…

math.CO2007

Zero-divisor graphs of amalgamated duplication of a ring along an ideal

Hamid Reza Maimani, Siamak Yassemi

Let $R$ be a commutative ring with identity and let $I$ be an ideal of $R$ . Let $R ⋈ I$ be the subring of $R \times R$ consisting of the elements $(r, r + i)$ for $r \in R$ and $i\in…