(Di)graph products, labelings and related results

(Di)graph products, labelings and related results

Gallian’s survey shows that there is a big variety of labelings of graphs. By means of (di)graphs products we can establish strong relations among some of them. Moreover, due to the freedom of one of the factors, we can also obtain enumerative results that provide lower bounds on the number of nonisomorphic labelings of a particular type. In this talk, we will focus in three of the (di)graphs p...

Digraph related constructions and the complexity of digraph homomorphism problems

The role of polymorphisms in determining the complexity of constraint satisfaction problems is well established. In this context we study the stability of CSP complexity and polymorphism properties under some basic graph theoretic constructions. As applications we observe a collapse in the applicability of algorithms for CSPs over directed graphs with both a total source and a total sink: the c...

Approximate results for rainbow labelings

A simple graph G = (V,E) is said to be antimagic if there exists a bijection f : E → [1, |E|] such that the addition of the values of f on edges incident to every vertex are pairwise different. The graph G = (V,E) is distance antimagic if there exists a bijection f : V → [1, |V |], such that ∀x, y ∈ V, ∑ xi∈N(x) f(xi) 6= ∑ xj∈N(y) f(xj). Using the polynomial method of Alon we prove that there a...

Tenacity and some related results

Conceptually graph vulnerability relates to the study of graphintactness when some of its elements are removed. The motivation forstudying vulnerability measures is derived from design and analysisof networks under hostile environment. Graph tenacity has been anactive area of research since the the concept was introduced in1992. The tenacity T(G) of a graph G is defined asbegin{center} $T(G)=di...

Further results on antimagic graph labelings