5,858 research outputs found
A Formulation of the Potential for Communication Condition using C2KA
An integral part of safeguarding systems of communicating agents from covert
channel communication is having the ability to identify when a covert channel
may exist in a given system and which agents are more prone to covert channels
than others. In this paper, we propose a formulation of one of the necessary
conditions for the existence of covert channels: the potential for
communication condition. Then, we discuss when the potential for communication
is preserved after the modification of system agents in a potential
communication path. Our approach is based on the mathematical framework of
Communicating Concurrent Kleene Algebra (C2KA). While existing approaches only
consider the potential for communication via shared environments, the approach
proposed in this paper also considers the potential for communication via
external stimuli.Comment: In Proceedings GandALF 2014, arXiv:1408.556
Kurt Gödel and Computability Theory
Although Kurt Gödel does not figure prominently in the history of computabilty theory, he exerted a significant influence on some of the founders of the field, both through his published work and through personal interaction. In particular, Gödel’s 1931 paper on incompleteness and the methods developed therein were important for the early development of recursive function theory and the lambda calculus at the hands of Church, Kleene, and Rosser. Church and his students studied Gödel 1931, and Gödel taught a seminar at Princeton in 1934. Seen in the historical context, Gödel was an important catalyst for the emergence of computability theory in the mid 1930s
A Swiss Pocket Knife for Computability
This research is about operational- and complexity-oriented aspects of
classical foundations of computability theory. The approach is to re-examine
some classical theorems and constructions, but with new criteria for success
that are natural from a programming language perspective.
Three cornerstones of computability theory are the S-m-ntheorem; Turing's
"universal machine"; and Kleene's second recursion theorem. In today's
programming language parlance these are respectively partial evaluation,
self-interpretation, and reflection. In retrospect it is fascinating that
Kleene's 1938 proof is constructive; and in essence builds a self-reproducing
program.
Computability theory originated in the 1930s, long before the invention of
computers and programs. Its emphasis was on delimiting the boundaries of
computability. Some milestones include 1936 (Turing), 1938 (Kleene), 1967
(isomorphism of programming languages), 1985 (partial evaluation), 1989 (theory
implementation), 1993 (efficient self-interpretation) and 2006 (term register
machines).
The "Swiss pocket knife" of the title is a programming language that allows
efficient computer implementation of all three computability cornerstones,
emphasising the third: Kleene's second recursion theorem. We describe
experiments with a tree-based computational model aiming for both fast program
generation and fast execution of the generated programs.Comment: In Proceedings Festschrift for Dave Schmidt, arXiv:1309.455
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