130 research outputs found
Hilbert Lattice Equations
There are five known classes of lattice equations that hold in every infinite
dimensional Hilbert space underlying quantum systems: generalised
orthoarguesian, Mayet's E_A, Godowski, Mayet-Godowski, and Mayet's E equations.
We obtain a result which opens a possibility that the first two classes
coincide. We devise new algorithms to generate Mayet-Godowski equations that
allow us to prove that the fourth class properly includes the third. An open
problem related to the last class is answered. Finally, we show some new
results on the Godowski lattices characterising the third class of equations.Comment: 24 pages, 3 figure
Evaluation of elicitation methods to quantify Bayes linear models
The Bayes linear methodology allows decision makers to express their subjective beliefs and adjust these beliefs as observations are made. It is similar in spirit to probabilistic Bayesian approaches, but differs as it uses expectation as its primitive. While substantial work has been carried out in Bayes linear analysis, both in terms of theory development and application, there is little published material on the elicitation of structured expert judgement to quantify models. This paper investigates different methods that could be used by analysts when creating an elicitation process. The theoretical underpinnings of the elicitation methods developed are explored and an evaluation of their use is presented. This work was motivated by, and is a precursor to, an industrial application of Bayes linear modelling of the reliability of defence systems. An illustrative example demonstrates how the methods can be used in practice
Kochen-Specker Vectors
We give a constructive and exhaustive definition of Kochen-Specker (KS)
vectors in a Hilbert space of any dimension as well as of all the remaining
vectors of the space. KS vectors are elements of any set of orthonormal states,
i.e., vectors in n-dim Hilbert space, H^n, n>3 to which it is impossible to
assign 1s and 0s in such a way that no two mutually orthogonal vectors from the
set are both assigned 1 and that not all mutually orthogonal vectors are
assigned 0. Our constructive definition of such KS vectors is based on
algorithms that generate MMP diagrams corresponding to blocks of orthogonal
vectors in R^n, on algorithms that single out those diagrams on which algebraic
0-1 states cannot be defined, and on algorithms that solve nonlinear equations
describing the orthogonalities of the vectors by means of statistically
polynomially complex interval analysis and self-teaching programs. The
algorithms are limited neither by the number of dimensions nor by the number of
vectors. To demonstrate the power of the algorithms, all 4-dim KS vector
systems containing up to 24 vectors were generated and described, all 3-dim
vector systems containing up to 30 vectors were scanned, and several general
properties of KS vectors were found.Comment: 19 pages, 6 figures, title changed, introduction thoroughly
rewritten, n-dim rotation of KS vectors defined, original Kochen-Specker 192
(117) vector system translated into MMP diagram notation with a new graphical
representation, results on Tkadlec's dual diagrams added, several other new
results added, journal version: to be published in J. Phys. A, 38 (2005). Web
page: http://m3k.grad.hr/pavici
Parity proofs of the Bell-Kochen-Specker theorem based on the 600-cell
The set of 60 real rays in four dimensions derived from the vertices of a
600-cell is shown to possess numerous subsets of rays and bases that provide
basis-critical parity proofs of the Bell-Kochen-Specker (BKS) theorem (a
basis-critical proof is one that fails if even a single basis is deleted from
it). The proofs vary considerably in size, with the smallest having 26 rays and
13 bases and the largest 60 rays and 41 bases. There are at least 90 basic
types of proofs, with each coming in a number of geometrically distinct
varieties. The replicas of all the proofs under the symmetries of the 600-cell
yield a total of almost a hundred million parity proofs of the BKS theorem. The
proofs are all very transparent and take no more than simple counting to
verify. A few of the proofs are exhibited, both in tabular form as well as in
the form of MMP hypergraphs that assist in their visualization. A survey of the
proofs is given, simple procedures for generating some of them are described
and their applications are discussed. It is shown that all four-dimensional
parity proofs of the BKS theorem can be turned into experimental disproofs of
noncontextuality.Comment: 19 pages, 11 tables, 3 figures. Email address of first author has
been corrected. Ref.[5] has been corrected, as has an error in Fig.3.
Formatting error in Sec.4 has been corrected and the placement of tables and
figures has been improved. A new paragraph has been added to Sec.4 and
another new paragraph to the end of the Appendi
Determination of Molecular Dissociation Rates from Measurements of Scattered Solar Ultraviolet Light
Scattereds olaru ltravioletl ight in the spectral region from 250 to 320 nm was measured from a balloon platform at altitudes ranging from 14.5 to 38.8 km with a wavelengthr esolutiono f approximately0 .3 nm and an accuracyin determiningth ew avelengthp ositiono f 0.5 nm. We usedt heses catterd atat o comparea ndv alidatea single scatteringm odel developedf or this purpose. Using these semi-empiricarl esults,w e constructedth e singles cattered component of the ultraviolet irradiance as a function of height and wavelength. From these data, it is possible to determinet he percentaged issociationra te of a variety of speciesd ue to scatteredu ltravioletr adiation. Theser esults are presenteda s a ratio of intensitiesR = I•/(I0+I0, where I• is the first order scatteringa nd I0 is the direct attenuated radiation from the sun. The attenuated direct radiation from the sun can be multiplied by the factor 1/(l-R), the Rayleigha mplificationr atio usedb y Nicolet et al. (1982), to include the contribution to the irradiance from first order scattered light. The results are multiplied by a cross sectiono f the speciesu nder considerationto obtain the dissociationra tes. Ozoneo verburdena nd an approximate ozone particle density altitude profile are obtained when validating the single scatter model
Parity proofs of the Kochen-Specker theorem based on 60 complex rays in four dimensions
It is pointed out that the 60 complex rays in four dimensions associated with
a system of two qubits yield over 10^9 critical parity proofs of the
Kochen-Specker theorem. The geometrical properties of the rays are described,
an overview of the parity proofs contained in them is given, and examples of
some of the proofs are exhibited.Comment: 17 pages, 13 tables, 3 figures. Several new references have been
adde
Critical noncolorings of the 600-cell proving the Bell-Kochen-Specker theorem
Aravind and Lee-Elkin (1997) gave a proof of the Bell-Kochen-Specker theorem
by showing that it is impossible to color the 60 directions from the center of
a 600-cell to its vertices in a certain way. This paper refines that result by
showing that the 60 directions contain many subsets of 36 and 30 directions
that cannot be similarly colored, and so provide more economical demonstrations
of the theorem. Further, these subsets are shown to be critical in the sense
that deleting even a single direction from any of them causes the proof to
fail. The critical sets of size 36 and 30 are shown to belong to orbits of 200
and 240 members, respectively, under the symmetries of the polytope. A
comparison is made between these critical sets and other such sets in four
dimensions, and the significance of these results is discussed.Comment: 2 new references added, caption to Table 9 correcte
Research strategies for organizational history:a dialogue between historical theory and organization theory
If history matters for organization theory, then we need greater reflexivity regarding the epistemological problem of representing the past; otherwise, history might be seen as merely a repository of ready-made data. To facilitate this reflexivity, we set out three epistemological dualisms derived from historical theory to explain the relationship between history and organization theory: (1) in the dualism of explanation, historians are preoccupied with narrative construction, whereas organization theorists subordinate narrative to analysis; (2) in the dualism of evidence, historians use verifiable documentary sources, whereas organization theorists prefer constructed data; and (3) in the dualism of temporality, historians construct their own periodization, whereas organization theorists treat time as constant for chronology. These three dualisms underpin our explication of four alternative research strategies for organizational history: corporate history, consisting of a holistic, objectivist narrative of a corporate entity; analytically structured history, narrating theoretically conceptualized structures and events; serial history, using replicable techniques to analyze repeatable facts; and ethnographic history, reading documentary sources "against the grain." Ultimately, we argue that our epistemological dualisms will enable organization theorists to justify their theoretical stance in relation to a range of strategies in organizational history, including narratives constructed from documentary sources found in organizational archives. Copyright of the Academy of Management, all rights reserved
- …