126 research outputs found
Orthomodular-Valued Models for Quantum Set Theory
In 1981, Takeuti introduced quantum set theory by constructing a model of set
theory based on quantum logic represented by the lattice of closed linear
subspaces of a Hilbert space in a manner analogous to Boolean-valued models of
set theory, and showed that appropriate counterparts of the axioms of
Zermelo-Fraenkel set theory with the axiom of choice (ZFC) hold in the model.
In this paper, we aim at unifying Takeuti's model with Boolean-valued models by
constructing models based on general complete orthomodular lattices, and
generalizing the transfer principle in Boolean-valued models, which asserts
that every theorem in ZFC set theory holds in the models, to a general form
holding in every orthomodular-valued model. One of the central problems in this
program is the well-known arbitrariness in choosing a binary operation for
implication. To clarify what properties are required to obtain the generalized
transfer principle, we introduce a class of binary operations extending the
implication on Boolean logic, called generalized implications, including even
non-polynomially definable operations. We study the properties of those
operations in detail and show that all of them admit the generalized transfer
principle. Moreover, we determine all the polynomially definable operations for
which the generalized transfer principle holds. This result allows us to
abandon the Sasaki arrow originally assumed for Takeuti's model and leads to a
much more flexible approach to quantum set theory.Comment: 25 pages, v2: to appear in Rev. Symb. Logic, v3: corrected typo
Probability Measures and projections on Quantum Logics
The present paper is devoted to modelling of a probability measure of logical
connectives on a quantum logic (QL), via a -map, which is a special map on
it. We follow the work in which the probability of logical conjunction,
disjunction and symmetric difference and their negations for non-compatible
propositions are studied.
We study such a -map on quantum logics, which is a probability measure
of a projection and show, that unlike classical (Boolean) logic, probability
measure of projections on a quantum logic are not necessarilly pure
projections.
We compare properties of a -map on QLs with properties of a probability
measure related to logical connectives on a Boolean algebra
Algebras of Measurements: the logical structure of Quantum Mechanics
In Quantum Physics, a measurement is represented by a projection on some
closed subspace of a Hilbert space. We study algebras of operators that
abstract from the algebra of projections on closed subspaces of a Hilbert
space. The properties of such operators are justified on epistemological
grounds. Commutation of measurements is a central topic of interest. Classical
logical systems may be viewed as measurement algebras in which all measurements
commute. Keywords: Quantum measurements, Measurement algebras, Quantum Logic.
PACS: 02.10.-v.Comment: Submitted, 30 page
A presentation of Quantum Logic based on an "and then" connective
When a physicist performs a quantic measurement, new information about the
system at hand is gathered. This paper studies the logical properties of how
this new information is combined with previous information. It presents Quantum
Logic as a propositional logic under two connectives: negation and the "and
then" operation that combines old and new information. The "and then"
connective is neither commutative nor associative. Many properties of this
logic are exhibited, and some small elegant subset is shown to imply all the
properties considered. No independence or completeness result is claimed.
Classical physical systems are exactly characterized by the commutativity, the
associativity, or the monotonicity of the "and then" connective. Entailment is
defined in this logic and can be proved to be a partial order. In orthomodular
lattices, the operation proposed by Finch (1969) satisfies all the properties
studied in this paper. All properties satisfied by Finch's operation in modular
lattices are valid in Hilbert Space Quantum Logic. It is not known whether all
properties of Hilbert Space Quantum Logic are satisfied by Finch's operation in
modular lattices. Non-commutative, non-associative algebraic structures
generalizing Boolean algebras are defined, ideals are characterized and a
homomorphism theorem is proved.Comment: 28 pages. Submitte
Categoricity and Possibility. A Note on Williamson's Modal Monism
The paper sketches an argument against modal monism, more specifically against the reduction of physical possibility to metaphysical possibility. The argument is based on the non-categoricity of quantum logic
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