Dickson Y. B. Annor

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20222026

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8 papers · 1 filter

math.CO2026

Induced Subgraph Bounds on the Zero Forcing Number and Chromatic Consequences

Dickson Y. B. Annor, Ben Howerton

Let $G$ be a graph with chromatic number $χ (G)$ , clique number $ω (G)$ and zero forcing number $Z (G)$ . We establish new lower bounds on $Z (G)$ in terms of induced triangle-free subg…

math.CO2026

A Two-Player Zero Forcing Game

Dickson Y. B. Annor, Ben Howerton

We introduce a competitive two-player zero forcing game on a connected graph. Alice and Bob alternately seed white vertices or perform legal zero forces in their own colours, and e…

math.CO2025

A Note on Inequalities for Three Domination Parameters

Dickson Y. B. Annor

In this short paper, we establish relations between the domination number $γ$ , the total domination number $γ_{t}$ , and the connected domination number $γ_{c}$ of a graph. In particula…

math.CO2025

Domination Parameters of Graph Covers

Dickson Y. B. Annor

A graph $G$ is a \emph{cover} of a graph $F$ if there exists an onto mapping $π : V (G) \to V (F)$ , called a (\emph{covering}) \emph{projection}, such that $π$ maps the neighbours of…

math.CO2024

Three Theorems on Negami's Planar Cover Conjecture

Dickson Annor, Yuri Nikolayevsky, Michael Payne

A long-standing Conjecture of S. Negami states that a connected graph has a finite planar cover if and only if it embeds in the projective plane. It is known that the Conjecture is…

math.CO2024

On $r$ -Equichromatic Lines with few points in $C^{2}$

Dickson Y. B. Annor

Let $P$ be a set of $n$ green and $n - k$ red points in $C^{2}$ . A line determined by $i$ green and $j$ red points such that $i + j \geq 2$ and $∣ i - j ∣ \leq r$ is called \emp…

math.CO2023

$K_{1, 2, 2, 2}$ has no $n$ -fold planar cover graph for $n < 14$

Dickson Y. B. Annor, Yuri Nikolayevsky, Michael S. Payne

S. Negami conjectured in $1988$ that a connected graph has a finite planar cover if and only if it embeds in the projective plane. It follows from the works of D. Archdeacon, M. Fe…

math.CO2022

A Note on the Number of Regions in a Line Arrangement

Dickson Y. B. Annor, Michael S. Payne

For an arrangement of $n$ lines in the real projective plane, we denote by $f$ the number of regions into which the real projective plane is divided by the lines. Using Bojanowski'…

Induced Subgraph Bounds on the Zero Forcing Number and Chromatic Consequences

A Two-Player Zero Forcing Game

A Note on Inequalities for Three Domination Parameters

Domination Parameters of Graph Covers

Three Theorems on Negami's Planar Cover Conjecture

On r-Equichromatic Lines with few points in C2

K1,2,2,2​ has no n-fold planar cover graph for n<14

A Note on the Number of Regions in a Line Arrangement

On $r$ -Equichromatic Lines with few points in $C^{2}$

$K_{1, 2, 2, 2}$ has no $n$ -fold planar cover graph for $n < 14$