17,158 research outputs found
Runtime Monitoring of Metric First-order Temporal Properties
We introduce a novel approach to the runtime monitoring of complex
system properties. In particular, we present an online algorithm for
a safety fragment of metric first-order temporal logic that
is considerably more expressive than the logics supported by prior
monitoring methods. Our approach, based on automatic structures,
allows the unrestricted use of negation, universal and existential
quantification over infinite domains, and the arbitrary nesting of
both past and bounded future operators. Moreover, we show how
to optimize our approach for the common case where
structures consist of only finite relations, over possibly infinite
domains. Under an additional restriction, we prove that the space
consumed by our monitor is polynomially bounded by the cardinality
of the data appearing in the processed prefix of the temporal
structure being monitored
On the undefinability of Tsirelson's space and its descendants
We prove that Tsirelson's space cannot be defined explicitly from the
classical Banach sequence spaces. We also prove that any Banach space that is
explicitly definable from a class of spaces that contain or must
contain or as well
Compactness of first-order fuzzy logics
One of the nice properties of the first-order logic is the compactness of
satisfiability. It state that a finitely satisfiable theory is satisfiable.
However, different degrees of satisfiability in many-valued logics, poses
various kind of the compactness in these logics. One of this issues is the
compactness of -satisfiability. Here, after an overview on the results
around the compactness of satisfiability and compactness of -satisfiability
in many-valued logic based on continuous t-norms (basic logic), we extend the
results around this topic. To this end, we consider a reverse semantical
meaning for basic logic. Then we introduce a topology on and
that the interpretation of all logical connectives are continuous with respect
to these topologies. Finally using this fact we extend the results around the
compactness of satisfiability in basic ogic
Decidability of the interval temporal logic ABBar over the natural numbers
In this paper, we focus our attention on the interval temporal logic of the
Allen's relations "meets", "begins", and "begun by" (ABBar for short),
interpreted over natural numbers. We first introduce the logic and we show that
it is expressive enough to model distinctive interval properties,such as
accomplishment conditions, to capture basic modalities of point-based temporal
logic, such as the until operator, and to encode relevant metric constraints.
Then, we prove that the satisfiability problem for ABBar over natural numbers
is decidable by providing a small model theorem based on an original
contraction method. Finally, we prove the EXPSPACE-completeness of the proble
Undecidable First-Order Theories of Affine Geometries
Tarski initiated a logic-based approach to formal geometry that studies
first-order structures with a ternary betweenness relation (\beta) and a
quaternary equidistance relation (\equiv). Tarski established, inter alia, that
the first-order (FO) theory of (R^2,\beta,\equiv) is decidable. Aiello and van
Benthem (2002) conjectured that the FO-theory of expansions of (R^2,\beta) with
unary predicates is decidable. We refute this conjecture by showing that for
all n>1, the FO-theory of monadic expansions of (R^2,\beta) is \Pi^1_1-hard and
therefore not even arithmetical. We also define a natural and comprehensive
class C of geometric structures (T,\beta), where T is a subset of R^2, and show
that for each structure (T,\beta) in C, the FO-theory of the class of monadic
expansions of (T,\beta) is undecidable. We then consider classes of expansions
of structures (T,\beta) with restricted unary predicates, for example finite
predicates, and establish a variety of related undecidability results. In
addition to decidability questions, we briefly study the expressivity of
universal MSO and weak universal MSO over expansions of (R^n,\beta). While the
logics are incomparable in general, over expansions of (R^n,\beta), formulae of
weak universal MSO translate into equivalent formulae of universal MSO.
This is an extended version of a publication in the proceedings of the 21st
EACSL Annual Conferences on Computer Science Logic (CSL 2012).Comment: 21 pages, 3 figure
An Optimal Decision Procedure for MPNL over the Integers
Interval temporal logics provide a natural framework for qualitative and
quantitative temporal reason- ing over interval structures, where the truth of
formulae is defined over intervals rather than points. In this paper, we study
the complexity of the satisfiability problem for Metric Propositional Neigh-
borhood Logic (MPNL). MPNL features two modalities to access intervals "to the
left" and "to the right" of the current one, respectively, plus an infinite set
of length constraints. MPNL, interpreted over the naturals, has been recently
shown to be decidable by a doubly exponential procedure. We improve such a
result by proving that MPNL is actually EXPSPACE-complete (even when length
constraints are encoded in binary), when interpreted over finite structures,
the naturals, and the in- tegers, by developing an EXPSPACE decision procedure
for MPNL over the integers, which can be easily tailored to finite linear
orders and the naturals (EXPSPACE-hardness was already known).Comment: In Proceedings GandALF 2011, arXiv:1106.081
Succinctness in subsystems of the spatial mu-calculus
In this paper we systematically explore questions of succinctness in modal
logics employed in spatial reasoning. We show that the closure operator,
despite being less expressive, is exponentially more succinct than the
limit-point operator, and that the -calculus is exponentially more
succinct than the equally-expressive tangled limit operator. These results hold
for any class of spaces containing at least one crowded metric space or
containing all spaces based on ordinals below , with the usual
limit operator. We also show that these results continue to hold even if we
enrich the less succinct language with the universal modality
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