On the Hajós number of graphs

G Gutin, AV Kostochka, B Toft - Discrete Mathematics, 2000 - Elsevier
… To support further our conjecture on the minimum possible product of the HajÃos number
of a graph and its complement, we find the minimum possible HajÃos number

The graph constructions of Hajós and Ore

A Urquhart - Journal of Graph Theory, 1997 - Wiley Online Library
… The procedure for adding an edge is essentially the same, except that we use the graphs
Kq[1] or Kq + e depending on whether the extra edge has a vertex in the copy of Kq or not. …

Some remarks on Hajós' conjecture

C Thomassen - Journal of Combinatorial Theory, Series B, 2005 - Elsevier
… We relate Hajós’ conjecture to Ramsey theory, perfect graphs, and the … On the other hand,
we show that some of the graphs which Catlin conjectured to be counterexamples to Hajós’ …

[PDF][PDF] Paare hajóssche graphen

A Kotzig - Časopis pro pěstování matematiky, 1963 - dml.cz
Hajos abgeleitet hatte und an welche er auf dem Kolloquium erinnerte (siehe z. B. die … Die
oben erwähnten Bedingungen, unter welchen ein Graph ein H-Graph ist, vermehren wir nun …

A note on graph colorings and graph polynomials

N Alon, M Tarsi - journal of combinatorial theory, Series B, 1997 - Elsevier
… , using Ore's version of Hajos' theorem. We also show that a certain weighted sum over the
proper k-colorings of a graph can be computed from its graph polynomial in a simple manner. …

Hajós-Type Constructions and Neighborhood Complexes

B Braun, J Vega - SIAM Journal on Discrete Mathematics, 2020 - SIAM
… into restrictions on Haj\'os-type constructions for graphs with … shortdistance"" identifications
on the first Betti number of N(G)… two graph construction algorithms based on different Haj\'os-…

Matrix representation–Hajos stable graphs

M Yamuna, K Karthika - IOP Conference Series: Materials …, 2017 - iopscience.iop.org
… In general two graphs are involved in binary operation. Hajos construction is one such … So
two graphs with three operations on vertices and edges increases the difficulty in implanting it. …

The complexity of the Hajós calculus

T Pitassi, A Urquhart - SIAM Journal on Discrete Mathematics, 1995 - SIAM
… isomorphic graphs with different labels as differentgraphs. Accordingly, we define a graph G
… We will showby downward induction on k (1 _< k <_ q- 1) that we can construct the graph G[…

On Gallai's and Haj\'os' Conjectures for graphs with treewidth at most 3

F Botler, M Sambinelli, RS Coelho, O Lee - arXiv preprint arXiv …, 2017 - arxiv.org
Hajós’ Conjecture, on the other hand, was verified only for graphs with maximum degree 4
and for planar graphs… In this paper, we verify Gallai’s and Hajós’ Conjectures for graphs with …

How to construct the symmetric cycle of length 5 using Haj\'os construction with an adapted Rank Genetic Algorithm

JC García-Altamirano, M Olsen… - Discrete …, 2023 - dmtcs.episciences.org
… nation and mutation operators from graph theory. The Hajós Join became the recombination
… digraph obtained by Hajós constructions of the complete symmetric digraph on 3 vertices D(…