341 research outputs found
Temporal Stream Logic: Synthesis beyond the Bools
Reactive systems that operate in environments with complex data, such as
mobile apps or embedded controllers with many sensors, are difficult to
synthesize. Synthesis tools usually fail for such systems because the state
space resulting from the discretization of the data is too large. We introduce
TSL, a new temporal logic that separates control and data. We provide a
CEGAR-based synthesis approach for the construction of implementations that are
guaranteed to satisfy a TSL specification for all possible instantiations of
the data processing functions. TSL provides an attractive trade-off for
synthesis. On the one hand, synthesis from TSL, unlike synthesis from standard
temporal logics, is undecidable in general. On the other hand, however,
synthesis from TSL is scalable, because it is independent of the complexity of
the handled data. Among other benchmarks, we have successfully synthesized a
music player Android app and a controller for an autonomous vehicle in the Open
Race Car Simulator (TORCS.
To Be Announced
In this survey we review dynamic epistemic logics with modalities for
quantification over information change. Of such logics we present complete
axiomatizations, focussing on axioms involving the interaction between
knowledge and such quantifiers, we report on their relative expressivity, on
decidability and on the complexity of model checking and satisfiability, and on
applications. We focus on open problems and new directions for research
Arbitrary Arrow Update Logic with Common Knowledge is neither RE nor co-RE
Arbitrary Arrow Update Logic with Common Knowledge (AAULC) is a dynamic
epistemic logic with (i) an arrow update operator, which represents a
particular type of information change and (ii) an arbitrary arrow update
operator, which quantifies over arrow updates.
By encoding the execution of a Turing machine in AAULC, we show that neither
the valid formulas nor the satisfiable formulas of AAULC are recursively
enumerable. In particular, it follows that AAULC does not have a recursive
axiomatization.Comment: In Proceedings TARK 2017, arXiv:1707.0825
Pre/post conditioned slicing
Th paper shows how analysis of programs in terms of pre- and postconditions can be improved using a generalisation of conditioned program slicing called pre/post conditioned slicing. Such conditions play an important role in program comprehension, reuse, verification and reengineering. Fully automated analysis is impossible because of the inherent undecidability of pre- and post- conditions. The method presented reformulates the problem to circumvent this. The reformulation is constructed so that programs which respect the pre- and post-conditions applied to them have empty slices. For those which do not respect the conditions, the slice contains statements which could potentially break the conditions. This separates the automatable part of the analysis from the human analysis
Propositional Reasoning about Safety and Termination of Heap-Manipulating Programs
This paper shows that it is possible to reason about the safety and
termination of programs handling potentially cyclic, singly-linked lists using
propositional reasoning even when the safety invariants and termination
arguments depend on constraints over the lengths of lists. For this purpose, we
propose the theory SLH of singly-linked lists with length, which is able to
capture non-trivial interactions between shape and arithmetic. When using the
theory of bit-vector arithmetic as a background, SLH is efficiently decidable
via a reduction to SAT. We show the utility of SLH for software verification by
using it to express safety invariants and termination arguments for programs
manipulating potentially cyclic, singly-linked lists with unrestricted,
unspecified sharing. We also provide an implementation of the decision
procedure and use it to check safety and termination proofs for several
heap-manipulating programs
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