Let B and R be two simple graphs with vertex set V , and let G(B,R) be the simple graph with vertex set V , in which two vertices are adjacent if they are adjacent in at least one of B and R. For X ⊆ V , we denote by B|X the subgraph of B induced by X; let R|X and G(B,R)|X be defined similarly. A clique in a graph is a set of pairwise adjacent vertices. A subset U ⊆ V is obedient if U is the un...

We give two constructions of strongly regular Cayley graphs on finite fields Fq by using union of cyclotomic classes and index 2 Gauss sums. In particular, we obtain twelve infinite families of strongly regular graphs with new parameters.

We give a construction of strongly regular Cayley graphs on finite fields Fq by using union of cyclotomic classes and index 4 Gauss sums. In particular, we obtain two infinite families of strongly regular graphs with new parameters.

Union-Find algorithm is a classic algorithm used to form the union of disjoined sets and find connected components of a graph from a given set of vertices and edges. The algorithm is often used in data manipulations that involve graphs, trees, hierarchies, and linked networks. A tree data structure can be used to implement the algorithm. A SAS data set is a tuple data structure that is excellen...

A graph of size n is said to be graceful when is possible toassign distinct integers from {0, 1, . . . , n} to its verticesand {|f(u)−f(v)| : uv ∈ E(G)} consists of n integers. Inthis paper we present broader families of graceful graphs; these families are obtained via three different operations: the third power of a caterpillar, the symmetric product of G and K2 , and the disjoint union of G a...

We study various optimization problems in t-subtree graphs, the intersection graphs of tsubtrees, where a t-subtree is the union of t disjoint subtrees of some tree. This graph class generalizes both the class of chordal graphs and the class of t-interval graphs, a generalization of interval graphs that has recently been studied from a combinatorial optimization point of view. We present approx...

This paper investigates the computational complexity of deciding whether the vertices of a graph can be partitioned into a disjoint union of cliques and a triangle-free subgraph. This problem is known to be NP-complete on arbitrary graphs. We show that this problem remains NP-complete even when restricted to planar graphs and perfect graphs.