Pseudo-Anosov flows in toroidal manifolds

We first prove rigidity results for pseudo-Anosov flows in prototypes of toroidal 3-manifolds: we show that a pseudo-Anosov flow in a Seifert fibered manifold is up to finite covers topologically equivalent to a geodesic flow and we show that a pseudo-Anosov flow in a solv manifold is topologically equivalent to a suspension Anosov flow. Then we study the interaction of a general pseudo-Anosov flow with possible Seifert fibered pieces in the torus decomposition: if the fiber is associated with a periodic orbit of the flow, we show that there is a standard and very simple form for the flow in the piece using Birkhoff annuli. This form is strongly connected with the topology of the Seifert piece. We also construct a large new class of examples in many graph manifolds, which is extremely general and flexible. We construct other new classes of examples, some of which are generalized pseudo-Anosov flows which have one prong singularities and which show that the above results in Seifert fibered and solvable manifolds do not apply to one prong pseudo-Anosov flows. Finally we also analyse immersed and embedded incompressible tori in optimal position with respect to a pseudo-Anosov flow.Comment: 44 pages, 4 figures. Version 2. New section 9: questions and comments. Overall revision, some simplified proofs, more explanation

Does Airport Regulation Benefit Consumers?

Airport regulation is aimed to impose price caps or other schemes on services supplied by airports to airlines that use them. However, it is not clear that regulation benefits the final consumers, the passengers. In the context of a very simple model, this paper finds out that this doesn’t always happen, and that passengers may be worse off with price capping than in an unregulated equilibrium. Besides, the paper provides an insight of the results of other regulation approaches (other than price caps) that have been suggested for airports.

Vertical Contracts between Airports and Airlines: is there a Trade-off between Welfare and Competitiveness?

Airports and airlines have been increasingly establishing vertical contracts, which have a wide variety of forms. These contracts have important implications for policy issues, namely for regulation and price discrimination legislation. In this paper we develop a model to analyse the effects of three types of vertical contracts, in what regards welfare, pro-competitiveness and the scope for regulation. We find that two types of contracts are anti-competitive, and that in all of them consumers are better-off, though in one of them within conditions regarding operational efficiency. We also conclude that regulation may (or may not) improve welfare depending on the type of contract and that price capping has different effects according to the facility the price of which is capped. Moreover, we find that these agreement’s effects exhibit a trade-off between pro-competitiveness and welfare and between price discrimination and welfare.vertical contracts, regulation, airports, airlines.

Quasi-Fuchsian AdS representations are Anosov

In a recent paper, Q. M\'erigot proved that representations in SO(2,n) of uniform lattices of SO(1,n) which are Anosov in the sense of Labourie are quasi-Fuchsian, i.e. are faithfull, discrete, and preserve an acausal subset in the boundary of anti-de Sitter space. In the present paper, we prove the reverse implication. It also includes: -- A construction of Dirichlet domains in the context of anti-de Sitter geometry, -- A proof that spatially compact globally hyperbolic anti-de Sitter spacetimes with acausal limit set admit locally CAT(-1) Cauchy hypersurfaces

Competition in complementary goods: Airport handling markets and Council Directive 96/67/EC

This paper addresses the case of complementary services with vertical relations. Using the example of airport handling activities, we develop a model to investigate the effects on welfare and competitiveness of four different handling market situations. We find out that the usual Cournot result on welfare when firms compete in complementary goods is verified unless there are efficiency gaps between the firms, or if vertically related firms also compete on the same market. We also find that the presence of a horizontally integrated firm may lead to market foreclosure. Moreover, we add a few remarks on regulatory issues, where we show that regulation may be pointless or even anti-competitive. In particular, we show that Council Directive 96/67/EC, while intending to increase competition, may lead to anti-competitive situations and consumers surplus decreases.Complementary goods competition; airport handling; vertical relations.