We relate the graph isomorphism problem to the solvability of certain systems of linear equations and linear inequalities. The number of these equations and inequalities is related to the complexity of the graphs isomorphism and subgraph isomorphim problems. 2000 Mathematics Subject Classification: 03D15, 05C50, 05C60, 15A48, 15A51, 15A69, 90C05.

We give the first systematic study of strong isomorphism reductions, a notion of reduction more appropriate than polynomial time reduction when, for example, comparing the computational complexity of the isomorphim problem for different classes of structures. We show that the partial ordering of its degrees is quite rich. We analyze its relationship to a further type of reduction between classe...

The purpose of this note is to extend Dynkin’s isomorphim involving functionals of the occupation field of a symmetric Markov processes and of the associated Gaussian field to a suitable class of non symmetric Markov processes. This was briefly proposed in [5] using Grassmann variables, extending to the non symmetric case some results of [4]. Here we propose an alternative approach, not relying...

The  present study aims at exploring the processing difficulty of cleft structures as a type of relative clause for EFL and Persian as  first language learners.The impact of head nouns with various functions as well as that of embedding on the processing of Persian and English cleft structures has been investigated in the present study.The participants  were 68  Iranian male and female students...

A concatenation of two vertex disjoint graphs is defined to be the graph obtained by identifying a vertex of one graph with a vertex of the other graph. We show that an arbitrary pair of connected graph can be uniquely reconstructed from the set of all their distinct concatenations, with only trivial exception. 1. The reconstruction problem. Let G1 and G2 be two vertex disjoint graphs, and let ...