Families of periodic horseshoe orbits in the restricted three-body problem

We compute families of symmetric periodic horseshoe orbits in the restricted three-body problem. Both the planar and three-dimensional cases are considered and several families are found.We describe how these families are organized as well as the behavior along and among the families of parameters such as the Jacobi constant or the eccentricity. We also determine the stability properties of individual orbits along the families. Interestingly, we find stable horseshoe-shaped orbit up to the quite high inclination of 17◦

A Note on the periodic orbits and topological entropy of graph maps

This paper deals with the relationship between the periodic orbits of continuous maps on graphs and the topological entropy of the map. We show that the topological entropy of a graph map can be approximated by the entropy of its periodic orbits

[Ressenya del llibre] Gould, Peter. Becoming a Geographer. Syracuse: Syracuse University Press, 1999; XIV + 350 p

Comentari al llibre de Peter Gould, titulat 'Becoming a Geographer' i publicat l' any 1999 per Syracuse University Press. Llibre que es pot considerar el testament de Peter Gold ja que conté una recopilació de textos escrits des del 1965 fins els anys 90, i que reflecteixen la seva formació acadèmica i les seves opinions sobre la pràctica de la geografia