Displaying similar documents to “On irregularities in the graph of generalized divisor functions”

Characterizing which Powers of Hypercubes and Folded Hyper- cubes Are Divisor Graphs

Eman A. AbuHijleh, Omar A. AbuGhneim, Hasan Al-Ezeh (2015)

Discussiones Mathematicae Graph Theory

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In this paper, we show that Qkn is a divisor graph, for n = 2, 3. For n ≥ 4, we show that Qkn is a divisor graph iff k ≥ n − 1. For folded-hypercube, we get FQn is a divisor graph when n is odd. But, if n ≥ 4 is even integer, then FQn is not a divisor graph. For n ≥ 5, we show that (FQn)k is not a divisor graph, where 2 ≤ k ≤ [n/2] − 1.

Some properties of the zero divisor graph of a commutative ring

Khalida Nazzal, Manal Ghanem (2014)

Discussiones Mathematicae - General Algebra and Applications

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Let Γ(R) be the zero divisor graph for a commutative ring with identity. The k-domination number and the 2-packing number of Γ(R), where R is an Artinian ring, are computed. k-dominating sets and 2-packing sets for the zero divisor graph of the ring of Gaussian integers modulo n, Γ(ℤₙ[i]), are constructed. The center, the median, the core, as well as the automorphism group of Γ(ℤₙ[i]) are determined. Perfect zero divisor graphs Γ(R) are investigated.

The range of the sum-of-proper-divisors function

Florian Luca, Carl Pomerance (2015)

Acta Arithmetica

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Answering a question of Erdős, we show that a positive proportion of even numbers are in the form s(n), where s(n) = σ(n) - n, the sum of proper divisors of n.

Graceful numbers.

Bhutani, Kiran R., Levin, Alexander B. (2002)

International Journal of Mathematics and Mathematical Sciences

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