Energy of strongly connected digraphs whose underlying graph is a cycle



Título del documento: Energy of strongly connected digraphs whose underlying graph is a cycle
Revista: Proyecciones (Antofagasta)
Base de datos: PERIÓDICA
Número de sistema: 000406121
ISSN: 0716-0917
Autores: 1
1
Instituciones: 1Universidad de Antioquia, Instituto de Matemáticas, Medellín, Antioquia. Colombia
Año:
Periodo: Dic
Volumen: 35
Número: 4
Paginación: 395-404
País: Chile
Idioma: Inglés
Tipo de documento: Artículo
Enfoque: Analítico
Resumen en inglés The energy of a digraph is defined as E (D) = Pn k=1 |Re (zk)|, where z1,...,zn are the eigenvalues of the adjacency matrix of D. This is a generalization of the concept of energy introduced by I. Gutman in 1978 [3]. When the characteristic polynomial of a digraph D is of the form φD (z) = b n X2 c k=0 (−1)k bk (D) zn−2k (0.1) where b0 (D)=1 and bk (D) ≥ 0 for all k, we show that E (D) = 2 π Z∞ 0 1 t2 ln ⎡ ⎢ ⎣ b n X2 c k=0 bk (D)t 2k ⎤ ⎥ (0.2) ⎦ dt This expression for the energy has many applications in the study of extremal values of the energy in special classes of digraphs. In this paper we consider the set D∗ (Cn) of all strongly connected digraphs whose underlying graph is the cycle Cn, and characterize those whose characteristic polynomial is of the form (0.1). As a consequence, we find the extremal values of the energy based on (0.2)
Disciplinas: Matemáticas
Palabras clave: Matemáticas aplicadas,
Matemáticas puras,
Combinatoria,
Teoría de gráficas,
Algebra lineal,
Digrafos,
Ciclos
Keyword: Mathematics,
Applied mathematics,
Pure mathematics,
Combinatorics,
Graph theory,
Linear algebra,
Digraphs,
Cycles
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