2,104 research outputs found
Linear resolutions of powers and products
The goal of this paper is to present examples of families of homogeneous
ideals in the polynomial ring over a field that satisfy the following
condition: every product of ideals of the family has a linear free resolution.
As we will see, this condition is strongly correlated to good primary
decompositions of the products and good homological and arithmetical properties
of the associated multi-Rees algebras. The following families will be discussed
in detail: polymatroidal ideals, ideals generated by linear forms and Borel
fixed ideals of maximal minors. The main tools are Gr\"obner bases and Sagbi
deformation
Clemson veterans project
The Clemson Veterans Project exist to honor the stories of combat veterans from conflicts throughout our country\u27s history and do so in a professional manner expected from a university with such a rich military heritage. The project collected over 70 interviews in HD video. All videos have been made public on Youtube. The project was started to assist the Library of Congress with its own Veterans History Project. Before interviewing each student must take an exam on the digital file preparation process, interview courtesy, and then conduct a practice interview where they behave exactly as if it was a real interview. The videos are put onto DVDs along with accompanying documentation and then shipped in bulk. Going above the requirements for the LoC, each shipment contains a flash drive with every video and document in a digital format. Special interviews are selected for post-production including a custom made introduction
Hennessy-Milner Logic with Greatest Fixed Points as a Complete Behavioural Specification Theory
There are two fundamentally different approaches to specifying and verifying
properties of systems. The logical approach makes use of specifications given
as formulae of temporal or modal logics and relies on efficient model checking
algorithms; the behavioural approach exploits various equivalence or refinement
checking methods, provided the specifications are given in the same formalism
as implementations.
In this paper we provide translations between the logical formalism of
Hennessy-Milner logic with greatest fixed points and the behavioural formalism
of disjunctive modal transition systems. We also introduce a new operation of
quotient for the above equivalent formalisms, which is adjoint to structural
composition and allows synthesis of missing specifications from partial
implementations. This is a substantial generalisation of the quotient for
deterministic modal transition systems defined in earlier papers
High Velocity Cloud Complex H: A Satellite of the Milky Way in a Retrograde Orbit?
Observations with the Green Bank Telescope of 21cm HI emission from the
high-velocity cloud Complex H suggest that it is interacting with the Milky
Way. A model in which the cloud is a satellite of the Galaxy in an inclined,
retrograde circular orbit reproduces both the cloud's average velocity and its
velocity gradient with latitude. The model places Complex H at approximately 33
kpc from the Galactic Center on a retrograde orbit inclined about 45 degrees to
the Galactic plane. At this location it has an HI mass > 6 10^6 Msun and
dimensions of at least 10 by 5 kpc. Some of the diffuse HI associated with the
cloud has apparently been decelerated by interaction with Galactic gas. Complex
H has similarities to the dwarf irregular galaxy Leo A and to some compact
high-velocity clouds, and has an internal structure nearly identical to parts
of the Magellanic Stream, with a pressure P/k about 100 cm^{-3} K.Comment: 12 pages includes 4 figures. To be published in Astrophysical Journal
Letters, 1 July 200
Stoics against stoics in Cudworth's "A Treatise of Freewill"
In his 'A Treatise of Freewill', Ralph Cudworth argues against Stoic determinism by drawing on what he takes to be other concepts found in Stoicism, notably the claim that some things are âup to usâ and that these things are the product of our choice. These concepts are central to the late Stoic Epictetus and it appears at first glance as if Cudworth is opposing late Stoic voluntarism against early Stoic determinism. This paper argues that in fact, despite his claim to be drawing on Stoic doctrine, Cudworth uses these terms with a meaning first articulated only later, by the Peripatetic commentator Alexander of Aphrodisias
Usersâ encounter with normative discourses on Facebook:A three-pronged analysis of user agency as power structure, nexus and reception
This study asks whether usersâ encounter with normative discourses of lifestyle, consumption, and health on social media such as Facebook gives rise to agency. The theoretical framework draws on reception analysis, for its implied, but central interest in agency that lies at the intersection of texts and audiences. Based on a critique of the âparticipatory paradigm,â a paradigm that situates the locus of agency in the structural opposition between senders and users, in the norms of rational deliberation or in the figure of the activist, gaps are identified which can be filled by adopting an explicit focus on the socio-cultural practices of ordinary audiences in their encounters with media discourses. The study investigates user agency on seven Facebook groups and pages with the help of a three-pronged perspective based on the notion of the mediaâaudience relationship as (1) power structure, (2) nexus, and (3) reception. The analysis reveals that the structure at play on these Facebook groups and pages does not encourage user agency. However, user agency manifests itself through user interactions and expressive sense-making processes associated with reception. The benefits of such audience agency are a public, collective, and communicative sense-making process and an expansion of the professionally controlled text
Addicting via hashtags: How is Twitter making addiction?
Persons, substances, bodies, consumption: an ever widening process of ââaddictingââ is underway in Western societies. In this article, we turn our attention to the production of addiction on the microblogging social media platform, Twitter, as an important emerging site in which the addicting of contemporary societies is also occurring. Our analysis explores two questions. First, we investigate the ways in which addiction is enacted via Twitter. How is addiction being made on Twitter? Second, we ask how the technology of Twitter itself is shaping meaning: how do the technological ââaffordancesââ of Twitter help constitute the kinds of addiction being materialized? While we find a multiplicity of meanings in the 140-character messages, we also find a pattern: a tendency toward extremesâaddiction riven between pain and pleasure. In addition, we find significant areas of commonality between approaches and notable silences around alternatives to common understandings of addiction. We argue that the constraints on communication imposed by Twitter technology afford a ââshorthandââ of addiction that is both revealing and productive. Illuminated is the importance of addiction as a piece of cultural shorthand that draws on and simultaneously reproduces simplistic, reductive addiction objects. In concluding, we consider what these realities of addiction being enacted through Twitter can tell us about contemporary conditions of possibility for drug use in society and for individual subjectivities and experiences
Few smooth d-polytopes with n lattice points
We prove that, for fixed n there exist only finitely many embeddings of
Q-factorial toric varieties X into P^n that are induced by a complete linear
system. The proof is based on a combinatorial result that for fixed nonnegative
integers d and n, there are only finitely many smooth d-polytopes with n
lattice points. We also enumerate all smooth 3-polytopes with at most 12
lattice points. In fact, it is sufficient to bound the singularities and the
number of lattice points on edges to prove finiteness.Comment: 20+2 pages; major revision: new author, new structure, new result
Banks' risk assessment of Swedish SMEs
Building on the literatures on asymmetric information and risk taking, this paper applies conjoint experiments to investigate lending officers' probabilities of supporting credit to established or existing SMEs. Using a sample of 114 Swedish lending officers, we test hypotheses concerning how information on the borrower's ability to repay the loan; alignment of risk preferences; and risk sharing affect their willingness to grant credit. Results suggest that features that reduce the risk to the bank and shift the risk to the borrower have the largest impact. The paper highlights the interaction between factors that influence the credit decision. Implications for SMEs, banks and research are discussed
A Very Sensitive 21cm Survey for Galactic High-Velocity HI
Very sensitive HI 21cm observations have been made in 860 directions at dec
>= -43deg in search of weak, Galactic, high-velocity HI emission lines at
moderate and high Galactic latitudes. One-third of the observations were made
toward extragalactic objects. The median 4-sigma detection level is NHI =
8x10^{17} cm^-2 over the 21' telescope beam. High-velocity HI emission is
detected in 37% of the directions; about half of the lines could not have been
seen in previous surveys. The median FWHM of detected lines is 30.3 km/s. High-
velocity HI lines are seen down to the sensitivity limit of the survey implying
that there are likely lines at still lower values of NHI. The weakest lines
have a kinematics and distribution on the sky similar to that of the strong
lines, and thus do not appear to be a new population. Most of the emission
originates from objects which are extended over several degrees; few appear to
be compact sources. At least 75%, and possibly as many as 90%, of the lines are
associated with one of the major high-velocity complexes. The Magellanic Stream
extends at least 10 deg to higher Galactic latitude than previously thought and
is more extended in longitude as well. Although there are many lines with low
column density, their numbers do not increase as rapidly as NHI^-1, so most of
the HI mass in the high-velocity cloud phenomenon likely resides in the more
prominent clouds. The bright HI features may be mere clumps within larger
structures, and not independent objects.Comment: 88 pages includes 22 figures Accepted for Publication in ApJ Suppl.
June 200
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