The H-force number h(G) of a hamiltonian graph G is the smallest cardinality of a set A ⊆ V (G) such that each cycle containing all vertices of A is hamiltonian. In this paper a lower and an upper bound of h(G) is given. Such graphs, for which h(G) assumes the lower bound are characterized by a cycle extendability property. The H-force number of hamiltonian graphs which are exactly 2-connected can be calculated by a decomposition formula.
@article{bwmeta1.element.doi-10_7151_dmgt_1923, author = {Erhard Hexel}, title = {On theH-Force Number of Hamiltonian Graphs and Cycle Extendability}, journal = {Discussiones Mathematicae Graph Theory}, volume = {37}, year = {2017}, pages = {79-88}, zbl = {1354.05078}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.doi-10_7151_dmgt_1923} }
Erhard Hexel. On theH-Force Number of Hamiltonian Graphs and Cycle Extendability. Discussiones Mathematicae Graph Theory, Tome 37 (2017) pp. 79-88. http://gdmltest.u-ga.fr/item/bwmeta1.element.doi-10_7151_dmgt_1923/