20,287 research outputs found
Canonical Proof nets for Classical Logic
Proof nets provide abstract counterparts to sequent proofs modulo rule
permutations; the idea being that if two proofs have the same underlying
proof-net, they are in essence the same proof. Providing a convincing proof-net
counterpart to proofs in the classical sequent calculus is thus an important
step in understanding classical sequent calculus proofs. By convincing, we mean
that (a) there should be a canonical function from sequent proofs to proof
nets, (b) it should be possible to check the correctness of a net in polynomial
time, (c) every correct net should be obtainable from a sequent calculus proof,
and (d) there should be a cut-elimination procedure which preserves
correctness. Previous attempts to give proof-net-like objects for propositional
classical logic have failed at least one of the above conditions. In [23], the
author presented a calculus of proof nets (expansion nets) satisfying (a) and
(b); the paper defined a sequent calculus corresponding to expansion nets but
gave no explicit demonstration of (c). That sequent calculus, called LK\ast in
this paper, is a novel one-sided sequent calculus with both additively and
multiplicatively formulated disjunction rules. In this paper (a self-contained
extended version of [23]), we give a full proof of (c) for expansion nets with
respect to LK\ast, and in addition give a cut-elimination procedure internal to
expansion nets - this makes expansion nets the first notion of proof-net for
classical logic satisfying all four criteria.Comment: Accepted for publication in APAL (Special issue, Classical Logic and
Computation
A proof-theoretic analysis of the classical propositional matrix method
The matrix method, due to Bibel and Andrews, is a proof procedure designed for automated theorem-proving. We show that underlying this method is a fully structured combinatorial model of conventional classical proof theory. © 2012 The Author, 2012. Published by Oxford University Press
Neural Mechanism of Language
This paper is based on our previous work on neural coding. It is a
self-organized model supported by existing evidences. Firstly, we briefly
introduce this model in this paper, and then we explain the neural mechanism of
language and reasoning with it. Moreover, we find that the position of an area
determines its importance. Specifically, language relevant areas are in the
capital position of the cortical kingdom. Therefore they are closely related
with autonomous consciousness and working memories. In essence, language is a
miniature of the real world. Briefly, this paper would like to bridge the gap
between molecule mechanism of neurons and advanced functions such as language
and reasoning.Comment: 6 pages, 3 figure
Open Graphs and Monoidal Theories
String diagrams are a powerful tool for reasoning about physical processes,
logic circuits, tensor networks, and many other compositional structures. The
distinguishing feature of these diagrams is that edges need not be connected to
vertices at both ends, and these unconnected ends can be interpreted as the
inputs and outputs of a diagram. In this paper, we give a concrete construction
for string diagrams using a special kind of typed graph called an open-graph.
While the category of open-graphs is not itself adhesive, we introduce the
notion of a selective adhesive functor, and show that such a functor embeds the
category of open-graphs into the ambient adhesive category of typed graphs.
Using this functor, the category of open-graphs inherits "enough adhesivity"
from the category of typed graphs to perform double-pushout (DPO) graph
rewriting. A salient feature of our theory is that it ensures rewrite systems
are "type-safe" in the sense that rewriting respects the inputs and outputs.
This formalism lets us safely encode the interesting structure of a
computational model, such as evaluation dynamics, with succinct, explicit
rewrite rules, while the graphical representation absorbs many of the tedious
details. Although topological formalisms exist for string diagrams, our
construction is discreet, finitary, and enjoys decidable algorithms for
composition and rewriting. We also show how open-graphs can be parametrised by
graphical signatures, similar to the monoidal signatures of Joyal and Street,
which define types for vertices in the diagrammatic language and constraints on
how they can be connected. Using typed open-graphs, we can construct free
symmetric monoidal categories, PROPs, and more general monoidal theories. Thus
open-graphs give us a handle for mechanised reasoning in monoidal categories.Comment: 31 pages, currently technical report, submitted to MSCS, waiting
review
Against the Virtual: Kleinherenbrink’s Externality Thesis and Deleuze’s Machine Ontology
Drawing from Arjen Kleinherenbrink's recent book, Against Continuity: Gilles Deleuze's Speculative Realism (2019), this paper undertakes a detailed review of Kleinherenbrink's fourfold "externality thesis" vis-Ă -vis Deleuze's machine ontology. Reading Deleuze as a philosopher of the actual, this paper renders Deleuzean syntheses as passive contemplations, pulling other (passive) entities into an (active) experience and designating relations as expressed through contraction. In addition to reviewing Kleinherenbrink's book (which argues that the machine ontology is a guiding current that emerges in Deleuze's work after Difference and Repetition) alongside much of Deleuze's oeuvre, we relate and juxtapose Deleuze's machine ontology to positions concerning externality held by a host of speculative realists. Arguing that the machine ontology has its own account of interaction, change, and novelty, we ultimately set to prove that positing an ontological "cut" on behalf of the virtual realm is unwarranted because, unlike the realm of actualities, it is extraneous to the structure of becoming-that is, because it cannot be homogenous, any theory of change vis-Ă -vis the virtual makes it impossible to explain how and why qualitatively different actualities are produced
Dual-Context Calculi for Modal Logic
We present natural deduction systems and associated modal lambda calculi for
the necessity fragments of the normal modal logics K, T, K4, GL and S4. These
systems are in the dual-context style: they feature two distinct zones of
assumptions, one of which can be thought as modal, and the other as
intuitionistic. We show that these calculi have their roots in in sequent
calculi. We then investigate their metatheory, equip them with a confluent and
strongly normalizing notion of reduction, and show that they coincide with the
usual Hilbert systems up to provability. Finally, we investigate a categorical
semantics which interprets the modality as a product-preserving functor.Comment: Full version of article previously presented at LICS 2017 (see
arXiv:1602.04860v4 or doi: 10.1109/LICS.2017.8005089
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