Alliances and entry in a simple airline network

This paper constructs an entry and code-sharing alliances game to demonstrate that the alliance between the incumbent carriers may play a significant role of entry deterrence in a given airline network. We show that incumbents can use the alliances as a credible threat to deter the entry of the potential entrants who have no significant cost advantage. This finding suggests that the role of the alliance in entry deterrence should be considered carefully when governments promote and maintain competition in the deregulated airline network markets.

Alliance Partner Choice in Markets with Vertical and Horizontal Externalities

This study investigates the choice between complementary and parallel alliances in a market with vertical and horizontal externalities. One composite goods firm competes with two components producers, each providing a complementary component of a differentiated com- posite good. Although the joint profits from a parallel alliance between the composite goods firm and a components producer are always larger than those from a complementary alliance between components producers, through Nash bargaining, a components producer prefers the complementary (parallel) alliance when the degree of product differentiation is sufficiently large (small). Combined with the result that a complementary alliance is socially preferable, our findings provide meaningful implications for antitrust policy.Complementary alliance; Parallel alliance; Nash bargaining; Antitrust policy

Open spaces in urban dwelling environments : regulations and realities, Taipei, Taiwan.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1982.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH.Includes bibliographical references (p. 64).Because the population density is so high and people need interior spaces so urgently, the open spaces in Taiwan are always limited to the minimum acceptable standards, set by regulations. Open spaces are not considered as important urban components, and are usually misused, and, in addition, regulations-in Taiwan put emphasis on the control of the quantity rather than the quality of the spaces. The issues of land utilization concerning encroachment, physical controls and maintenance are critical and require careful scrutiny with regard to open spaces. The study analyzes the existing land utilization of the open spaces in the residential areas of Taipei and compares it to the current regulations. The objectives are: 1) To determine the reasons for the mismatches between the existing environment and the "legal environment" resulting from the regulations, and 2) To acquire feedback from the environment concerning revisions of the regulations. The intent throughout is to be descriptive and expositive rather than critical.M.S

Saddle-like topological surface states on the TT'X family of compounds (T, T' = Transition metal, X= Si, Ge)

Topological nodal-line semimetals are exotic conductors that host symmetry-protected conducting nodal-lines in their bulk electronic spectrum and nontrivial drumhead states on the surface. Based on first-principles calculations and an effective model analysis, we identify the presence of topological nodal-line semimetal states in the TT'X family of compounds (T, T' = transition metal, X= Si, or Ge) in the absence of spin-orbit coupling (SOC). Taking ZrPtGe as an exemplar system, we show that this material harbors a single nodal line on the $k_y=0$ plane, which is protected by the $M_y$ mirror plane symmetry. Surface electronic structure calculations further reveal the existence of a drumhead surface state nested inside the nodal line projection on the (010) surface with a saddle-like energy dispersion. When the SOC is included, the nodal line gaps out and the system transitions to a strong topological insulator state with $Z_2=(1;000)$. The topological surface state evolves from the drumhead surface state via the sharing of its saddle-like energy dispersion within the bulk energy gap. These features differ remarkably from those of the currently known topological surface states in topological insulators such as Bi$_2$Se$_3$ with Dirac-cone-like energy dispersions.Comment: 4 figure

Topological phase transition and quantum spin Hall state in TlBiS2_2

We have investigated the bulk and surface electronic structures and band topology of TlBiS$_2$ as a function of strain and electric field using \textit{ab-initio} calculations. In its pristine form, TlBiS$_2$ is a normal insulator, which does not support any non-trivial surface states. We show however that a compressive strain along the (111) direction induces a single band inversion with Z$_2$ = (1;000), resulting in a Dirac cone surface state with a large in-plane spin polarization. Our analysis shows that a critical point lies between the normal and topological phases where the dispersion of the 3D bulk Dirac cone at the $\Gamma$-point becomes nearly linear. The band gap in thin films of TlBiS$_2$ can be tuned through an out-of-the-plane electric field to realize a topological phase transition from a trivial insulator to a quantum spin Hall state. An effective $\mathbf{k \cdot p}$ model Hamiltonian is presented to simulate our first-principles results on TlBiS$_2$.Comment: 7 pages, 6 figures, Accepted for publication in JA