9,221 research outputs found
Innovation and the Evolution of Market Structure for Internet Access in the United States
How and why did the U.S. commercial Internet access market structure evolve during its first decade? Commercial Internet access market structure arose from a propitious combination of inherited market structures from communications and computing, where a variety of firms already flourished and entrepreneurial norms prevailed. This setting nurtured innovative behavior across such key features as pricing, operational practices, and geographic coverage. Inherited regulatory decisions in communications markets had a nurturing effect on innovative activity. On-going regulatory decisions also shaped the market’s evolution, sometimes nurturing innovation and sometimes not. This narrative and analysis informs conjectures about several unique features of U.S. market structure and innovative behavior. It also informs policy debates today about the role of regulation in nurturing or discouraging innovation behavior.
Building and Delivering the Virtual World: Commercializing Services for Internet Access
This study analyzes the service offerings of Internet Service Providers (ISPs), the commercial suppliers of Internet access in the United States. It presents data on the services of 2089 ISPs in the summer of 1998. By this time, the Internet access industry had undergone its first wave of entry and many ISPs had begun to offer services other than basic access. This paper develops an Internet access industry product code which classifies these services. Significant heterogeneity across ISPs is found in the propensity to offer these services, a pattern with an unconditional urban/rural difference. Most of the explained variance in behavior arises from firm-specific factors, with only weak evidence of location-specific factors for some services. These findings provide a window to the variety of approaches taken to build viable businesses organizations, a vital structural feature of this young market.
Filtrations and completions of certain positive level modules of affine algebras
We define a filtration indexed by the integers on the tensor product of an
integrable highest weight module and a loop module for a quantum affine
algebra. We prove that the filtration is either trivial or strictly decreasing
and give sufficient conditions for this to happen. In the first case we prove
that the module is irreducible and in the second case we prove that the
intersection of all the modules is zero, thus allowing us to define the
completed tensor product. In certain special cases, we identify the subsequent
quotients of filtration. These are certain highest weight integrable modules
and the multiplicity and the highest weight are the same as that obtained by
decomposing the tensor product of the highest weight crystal bases with the
crystal bases of a loop module
Nurturing the Accumulation of Innovations: Lessons from the Internet
The innovations that became the foundation for the Internet originate from two eras that illustrate two distinct models for accumulating innovations over the long haul. The pre-commercial era illustrates the operation of several useful non-market institutional arrangements. It also illustrates a potential drawback to government sponsorship – in this instance, truncation of exploratory activity. The commercial era illustrates a rather different set of lessons. It highlights the extraordinary power of market-oriented and widely distributed investment and adoption, which illustrates the power of market experimentation to foster innovative activity. It also illustrates a few of the conditions necessary to unleash value creation from such accumulated lessons, such as standards development and competition, and nurturing legal and regulatory policies.
Quantum loop modules
We classify the simple infinite dimensional integrable modules with finite
dimensional weight spaces over the quantized enveloping algebra of an untwisted
affine algebra. We prove that these are either highest (lowest) weight
integrable modules or simple submodules of a loop module of a
finite-dimensional simple integrable module and describe the latter class.
Their characters and crystal bases theory are discussed in a special case.Comment: 25 pages, AMSLaTe
Minimal affinizations as projective objects
We prove that the specialization to q=1 of a Kirillov-Reshetikhin module for
an untwisted quantum affine algebra of classical type is projective in a
suitable category. This yields a uniform character formula for the
Kirillov-Reshetikhin modules. We conjecture that these results holds for
specializations of minimal affinization with some restriction on the
corresponding highest weight. We discuss the connection with the conjecture of
Nakai and Nakanishi on q-characters of minimal affinizations. We establish this
conjecture in some special cases. This also leads us to conjecture an
alternating sum formula for Jacobi-Trudi determinants.Comment: 25 page
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