722 research outputs found
A logic with temporally accessible iteration
Deficiency in expressive power of the first-order logic has led to developing
its numerous extensions by fixed point operators, such as Least Fixed-Point
(LFP), inflationary fixed-point (IFP), partial fixed-point (PFP), etc. These
logics have been extensively studied in finite model theory, database theory,
descriptive complexity. In this paper we introduce unifying framework, the
logic with iteration operator, in which iteration steps may be accessed by
temporal logic formulae. We show that proposed logic FO+TAI subsumes all
mentioned fixed point extensions as well as many other fixed point logics as
natural fragments. On the other hand we show that over finite structures FO+TAI
is no more expressive than FO+PFP. Further we show that adding the same
machinery to the logic of monotone inductions (FO+LFP) does not increase its
expressive power either
Finite Model Finding for Parameterized Verification
In this paper we investigate to which extent a very simple and natural
"reachability as deducibility" approach, originated in the research in formal
methods in security, is applicable to the automated verification of large
classes of infinite state and parameterized systems. The approach is based on
modeling the reachability between (parameterized) states as deducibility
between suitable encodings of states by formulas of first-order predicate
logic. The verification of a safety property is reduced to a pure logical
problem of finding a countermodel for a first-order formula. The later task is
delegated then to the generic automated finite model building procedures. In
this paper we first establish the relative completeness of the finite
countermodel finding method (FCM) for a class of parameterized linear arrays of
finite automata. The method is shown to be at least as powerful as known
methods based on monotonic abstraction and symbolic backward reachability.
Further, we extend the relative completeness of the approach and show that it
can solve all safety verification problems which can be solved by the
traditional regular model checking.Comment: 17 pages, slightly different version of the paper is submitted to
TACAS 201
Temporal logic with predicate abstraction
A predicate linear temporal logic LTL_{\lambda,=} without quantifiers but
with predicate abstraction mechanism and equality is considered. The models of
LTL_{\lambda,=} can be naturally seen as the systems of pebbles (flexible
constants) moving over the elements of some (possibly infinite) domain. This
allows to use LTL_{\lambda,=} for the specification of dynamic systems using
some resources, such as processes using memory locations, mobile agents
occupying some sites, etc. On the other hand we show that LTL_{\lambda,=} is
not recursively axiomatizable and, therefore, fully automated verification of
LTL_{\lambda,=} specifications is not, in general, possible.Comment: 14 pages, 4 figure
Finite Countermodel Based Verification for Program Transformation (A Case Study)
Both automatic program verification and program transformation are based on
program analysis. In the past decade a number of approaches using various
automatic general-purpose program transformation techniques (partial deduction,
specialization, supercompilation) for verification of unreachability properties
of computing systems were introduced and demonstrated. On the other hand, the
semantics based unfold-fold program transformation methods pose themselves
diverse kinds of reachability tasks and try to solve them, aiming at improving
the semantics tree of the program being transformed. That means some
general-purpose verification methods may be used for strengthening program
transformation techniques. This paper considers the question how finite
countermodels for safety verification method might be used in Turchin's
supercompilation method. We extract a number of supercompilation sub-algorithms
trying to solve reachability problems and demonstrate use of an external
countermodel finder for solving some of the problems.Comment: In Proceedings VPT 2015, arXiv:1512.0221
The main components of CIS countries trade in the world economy
ОСНОВНЫЕ СОСТАВЛЯЮЩИЕ ТОРГОВЛИ СТРАН СНГ
В МИРОВОЙ ЭКОНОМИКЕ
Е. ЛИСИЦАUsing statistical data, the author analyzes foreign trade of CIS countries in 2016 in comparison with
2005, main reason of foreign trade and economic growth of CIS countries. As a result, it allows to define the
main trends and direction of foreign trade of CIS countries, and its specialization.=На основе анализа статистических данных в статье рассмотрена внешняя торговля стран СНГ
в 2016 году в сравнении с 2005 годом, основные составляющие торговли и экономического развития
стран СНГ. Это позволило выделить особенности и тенденции развития, а также специализацию
стран СНГ в мировой экономике
Efficient First-Order Temporal Logic for Infinite-State Systems
In this paper we consider the specification and verification of
infinite-state systems using temporal logic. In particular, we describe
parameterised systems using a new variety of first-order temporal logic that is
both powerful enough for this form of specification and tractable enough for
practical deductive verification. Importantly, the power of the temporal
language allows us to describe (and verify) asynchronous systems, communication
delays and more complex properties such as liveness and fairness properties.
These aspects appear difficult for many other approaches to infinite-state
verification.Comment: 16 pages, 2 figure
- …