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A complex unit gain graph (or ${\mathbb T}$-gain graph) is a triple $\Phi=(G, {\mathbb T}, \varphi)$ (or $(G, \varphi)$ for short) consisting of a simple graph $G$, as the underlying graph of $(G, \varphi)$, the set of unit complex numbers…

Combinatorics · Mathematics 2020-01-07 Shengjie He , Rong-Xia Hao , Fengming Dong

A complex unit gain graph (or $\mathbb{T}$-gain graph) is a triple $\Phi=(G, \mathbb{T}, \varphi)$ ($(G, \varphi)$ for short) consisting of a graph $G$ as the underlying graph of $(G, \varphi)$, $\mathbb{T}= \{ z \in C:|z|=1 \} $ is a…

Combinatorics · Mathematics 2019-09-19 Shengjie He , Rong-Xia Hao , Aimei Yu

A complex unit gain graph is a triple $\varphi=(G, \mathbb{T}, \varphi)$ (or $G^{\varphi}$ for short) consisting of a simple graph $G$, as the underlying graph of $G^{\varphi}$, the set of unit complex numbers $\mathbb{T}={z\in \mathbb{C}:…

Combinatorics · Mathematics 2021-08-04 Yong Lu , Qi Wu

Let $\Phi=(G, \varphi)$ be a complex unit gain graph (or $\mathbb{T}$-gain graph) and $A(\Phi)$ be its adjacency matrix, where $G$ is called the underlying graph of $\Phi$. The rank of $\Phi$, denoted by $r(\Phi)$, is the rank of $A(\Phi)$.…

Combinatorics · Mathematics 2017-12-01 Yong Lu , Ligong Wang , Qiannan Zhou

A complex unit gain graph ($ \mathbb{T} $-gain graph), $ \Phi=(G, \varphi) $ is a graph where the gain function $ \varphi $ assigns a unit complex number to each orientation of an edge of $ G $ and its inverse is assigned to the opposite…

Combinatorics · Mathematics 2023-12-29 Aniruddha Samanta , M. Rajesh Kannan

A $\mathbb{T}$-gain graph, $\Phi = (G, \varphi)$, is a graph in which the function $\varphi$ assigns a unit complex number to each orientation of an edge, and its inverse is assigned to the opposite orientation. The associated adjacency…

Combinatorics · Mathematics 2020-05-19 Aniruddha Samanta , M. Rajesh Kannan

Let $\Phi=(G,U(\mathbb{Q}),\varphi)$ be a quaternion unit gain graph (or $U(\mathbb{Q})$-gain graph). The adjacency matrix of $\Phi$ is denoted by $A(\Phi)$ and the left row rank of $\Phi$ is denoted by $r(\Phi)$. If $\Phi$ has at least one…

Combinatorics · Mathematics 2024-12-25 Yong Lu , Qi Shen , JiaXu Zhong

A complex unit gain graph ($ \mathbb{T} $-gain graph), $ \Phi=(G, \varphi) $ is a graph where the function $ \varphi $ assigns a unit complex number to each orientation of an edge of $ G $, and its inverse is assigned to the opposite…

Combinatorics · Mathematics 2021-01-28 Aniruddha Samanta , M. Rajesh Kannan

A complex unit gain graph (or a $\mathbb{T}$-gain graph) $\Theta(\Sigma,\varphi)$ is a graph where the unit complex number is assign by a function $\varphi$ to every oriented edge of $\Sigma$ and assign its inverse to the opposite…

Combinatorics · Mathematics 2024-04-29 Suliman Khan

A complex unit gain graph is a graph where each orientation of an edge is given a complex unit, which is the inverse of the complex unit assigned to the opposite orientation. We extend some fundamental concepts from spectral graph theory to…

Combinatorics · Mathematics 2014-08-26 Nathan Reff

A complex unit gain graph ($ \mathbb{T} $-gain graph), $ \Phi=(G, \varphi) $ is a graph where the function $ \varphi $ assigns a unit complex number to each orientation of an edge of $ G $, and its inverse is assigned to the opposite…

Combinatorics · Mathematics 2025-07-30 Aniruddha Samanta , Deepshikha

A $\mathbb{T}$-gain graph is a simple graph in which a unit complex number is assigned to each orientation of an edge, and its inverse is assigned to the opposite orientation. The associated adjacency matrix is defined canonically, and is…

Combinatorics · Mathematics 2023-04-18 Aniruddha Samanta , M. Rajesh Kannan

A complex unit gain graph is a simple graph in which each orientation of an edge is given a complex number with modulus 1 and its inverse is assigned to the opposite orientation of the edge. In this article, first we establish bounds for…

Combinatorics · Mathematics 2019-10-04 Ranjit Mehatari , M. Rajesh Kannan , Aniruddha Samanta

A complex unit gain graph ($\mathbb{T}$-gain graph), $\Phi = (G, \varphi)$ is a graph where the function $\varphi$ assigns a unit complex number to each orientation of an edge of $G$, and its inverse is assigned to the opposite orientation.…

Combinatorics · Mathematics 2021-05-11 M. Rajesh Kannan , Navish Kumar , Shivaramakrishna Pragada

We obtain a bound on the girth g of a quaternion unit gain graph in terms of the rank r of its adjacency matrix. In particular, we show that g <= r + 2 and characterize all quaternion unit gain graphs for which g = r+2. This extends…

Combinatorics · Mathematics 2024-12-02 Suliman Khan , Edwin R. van Dam

Let $\Phi=(G,U(\mathbb{Q}),\varphi)$ be a quaternion unit gain graph (or $U(\mathbb{Q})$-gain graph) of order $n$, $A(\Phi)$ be the adjacency matrix of $\Phi$ and $r(\Phi)$ be the row left rank of $\Phi$. Let $\Delta$ be the maximum degree…

Combinatorics · Mathematics 2025-04-10 Yong Lu , Qi Shen

Let $ \Phi=(G, \varphi) $ be a connected complex unit gain graph ($ \mathbb{T} $-gain graph) on a simple graph $ G $ with $ n $ vertices and maximum vertex degree $ \Delta $. The associated adjacency matrix and degree matrix are denoted by…

Combinatorics · Mathematics 2021-01-12 Aniruddha Samanta , M. Rajesh Kannan

Let $\widetilde{G}=(G,U(\mathbb{Q}),\varphi)$ be a quaternion unit gain graph (or $U(\mathbb{Q})$-gain graph), where $G$ is the underlying graph of $\widetilde{G}$, $U(\mathbb{Q})=\{q\in \mathbb{Q}: |q|=1\}$ and…

Combinatorics · Mathematics 2025-04-11 Yong Lu , Qi Shen

Complex unit gain graphs may exhibit various kinds of symmetry. In this work, we explore structural symmetry, spectral symmetry and sign-symmetry in such graphs, and their respective relations to one-another. Our main result is a…

Combinatorics · Mathematics 2024-10-04 Pepijn Wissing , Edwin R. van Dam

Let $G_w$ be a weighted graph. The \textit{inertia} of $G_w$ is the triple $In(G_w)=\big(i_+(G_w),i_-(G_w), $ $ i_0(G_w)\big)$, where $i_+(G_w),i_-(G_w),i_0(G_w)$ are the number of the positive, negative and zero eigenvalues of the…

Combinatorics · Mathematics 2013-07-02 Guihai Yu , Xiao-Dong Zhang , Lihua Feng
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