Market structure and competition: an empirical analysis of the U.S. airline industry

This thesis studies degree of competitiveness in the airline industry inferred by investigation of market structure. Chapter 2 documents empirical evidence that endogenous sunk costs investments in advertising and in expanding route network play a crucial role in determining equilibrium market structure and, that the industry is a natural oligopoly. In chapter 3 we perform an empirical analysis of market structure beyond the bounds approach, to explain firm numbers and market share asymmetry for city pair markets. In addition, splitting firms into two types, leaders and non-leaders, it is proposed evidence that nature of competition depends on presence of leader airlines. In particular, there is evidence consistent with learning; that is, non-leaders infer profitability of routes from the number and identity of leaders. Chapter 4 proposes two econometric models of entry to analyze market sharing agreements

Strichartz estimates for the metaplectic representation

We provide new estimates for the matrix coefficients of the metaplectic representation, inspired by a formal analogy with the Strichartz estimates which hold for several classes of evolution propagators U(t). The one parameter group of unitary operators U(t) is replaced by a unitary representation of a non-compact Lie group, the group element playing the role of time; the case of the metaplectic or oscillatory representation is of special interest in this connection, because the Schroedinger group is a subgroup of the metaplectic group. We prove uniform weak-type sharp estimates for matrix coefficients and Strichartz-type estimates for that representation. The crucial point is the choice of function spaces able to detect such a decay, which in general will depend on the given group action. The relevant function spaces here turn out to be the so-called modulation spaces from Time-frequency Analysis in Euclidean space, and Lebesgue spaces with respect to Haar measure on the metaplectic group. The proofs make use in an essential way of the covariance of the Wigner distribution with respect to the metaplectic representation

BMO Spaces on Weighted Homogeneous Trees

We consider an infinite homogeneous tree V endowed with the usual metric d defined on graphs and a weighted measure μ. The metric measure space (V, d, μ) is nondoubling and of exponential growth, hence the classical theory of Hardy and BMO spaces does not apply in this setting. We introduce a space BMO(μ) on (V, d, μ) and investigate some of its properties. We prove in particular that BMO(μ) can be identified with the dual of a Hardy space H1(μ) introduced in a previous work and we investigate the sharp maximal function related with BMO(μ)

Ice discharge of eastern Dome C drainage area, Antarctica, determined from airborne radar survey and satellite image analysis

Eastern Dome C, southern Talos Dome and northern Taylor Dome are drained by the Priestley, Reeves, David, Mawson and Mackay outlet glaciers, which flow into the Scott Coast on the west side of the Ross Sea, Antarctica. Airborne radar surveys were conducted on these glaciers to determine ice thickness and bed morphology along transverse and longitudinal profiles of the grounded and floating segments. A new analysis of a Landsat Thematic Mapper satellite image using a tracking technique was used to measure ice velocity at grounding lines and along ice tongues. The integration of radar and satellite data helped to locate grounding lines and to calculate the ice discharge. Changes in ice fluxes of floating glaciers were used to determine basal melting and freezing rates. The ice discharge calculated is less than half that required for a zero net surface mass balance according to the inputs given by the accumulation estimates widely adopted at present. The basal melting rates of meteoric ice represent 50% of the net ablation rate

Analysis on Trees with Nondoubling Flow Measures

We consider trees with root at infinity endowed with flow measures, which are nondoubling measures of at least exponential growth and which do not satisfy the isoperimetric inequality. In this setting, we develop a Calderón–Zygmund theory and we define BMO and Hardy spaces, proving a number of desired results extending the corresponding theory as known in more classical settings

ESTIMATES FOR MATRIX COEFFICIENTS OF REPRESENTATIONS

Estimates for matrix coefficients of unitary representations of semisimple Lie groups have been studied for a long time, starting with the seminal work by Bargmann, by Ehrenpreis and Mautner, and by Kunze and Stein. Two types of estimates have been established: on the one hand, Lp estimates, which are a dual formulation of the Kunze-Stein phenomenon, and which hold for all matrix coef-ficients, and on the other pointwise estimates related to asymptotic expansions at infinity, which are more precise but only hold for a restricted class of matrix coefficients. In this paper we prove a new type of estimate for the irreducibile unitary representations of SL(2, R) and for the so-called meta-plectic representation, which we believe has the best features of, and implies, both forms of estimate described above. As an application outside representation theory, we prove a new L2 estimate of dispersive type for the free Schro center dot dinger equation in Rn

Using Fluorescent Viruses for Detecting Bacteria in Water

A method of detecting water-borne pathogenic bacteria is based partly on established molecular-recognition and fluorescent-labeling concepts, according to which bacteria of a species of interest are labeled with fluorescent reporter molecules and the bacteria can then be detected by fluorescence spectroscopy. The novelty of the present method lies in the use of bacteriophages (viruses that infect bacteria) to deliver the fluorescent reporter molecules to the bacteria of the species of interest