On graphs with prescribed subgraphs of order , and a theorem of Kelly and Merriell
On hereditary properties of composition graphs
The composition graph of a family of n+1 disjoint graphs is the graph H obtained by substituting the n vertices of H₀ respectively by the graphs H₁,H₂,...,Hₙ. If H has some hereditary property P, then necessarily all its factors enjoy the same property. For some sort of graphs it is sufficient that all factors have a certain common P to endow H with this P. For instance, it is known that the composition graph of a family of perfect graphs is also a perfect graph (B. Bollobas, 1978), and the...
On highly closed cellular algebras and highly closed isomorphisms.
On homomorphism perfect graphs
On -pairable graphs from trees
The concept of the -pairable graphs was introduced by Zhibo Chen (On -pairable graphs, Discrete Mathematics 287 (2004), 11–15) as an extension of hypercubes and graphs with an antipodal isomorphism. In the same paper, Chen also introduced a new graph parameter , called the pair length of a graph , as the maximum such that is -pairable and if is not -pairable for any positive integer . In this paper, we answer the two open questions raised by Chen in the case that the graphs involved...
On Principal Graphs and Weak Duality.
On self-complementary cyclic packing of forests.
On some non-obvious connections between graphs and unary partial algebras
In the present paper we generalize a few algebraic concepts to graphs. Applying this graph language we solve some problems on subalgebra lattices of unary partial algebras. In this paper three such problems are solved, other will be solved in papers [Pió I], [Pió II], [Pió III], [Pió IV]. More precisely, in the present paper first another proof of the following algebraic result from [Bar1] is given: for two unary partial algebras and , their weak subalgebra lattices are isomorphic if and only...
On star polynomials, graphical partitions and reconstruction.
On the automorphism group of integral circulant graphs.
On the reconstruction of the matching polynomial and the reconstruction conjecture.
On Ulam's hypothesis