1,655 research outputs found
Multiple Congruence Relations, First-Order Theories on Terms, and the Frames of the Applied Pi-Calculus
International audienceWe investigate the problem of deciding first-order theories of finite trees with several distinguished congruence relations, each of them given by some equational axioms. We give an automata-based solution for the case where the different equational axiom systems are linear and variable-disjoint (this includes the case where all axioms are ground), and where the logic does not permit to express tree relations x=f(y,z). We show that the problem is undecidable when these restrictions are relaxed. As motivation and application, we show how to translate the model-checking problem of Apil, a spatial equational logic for the applied pi-calculus, to the validity of first-order formulas in term algebras with multiple congruence relations
Psi-calculi: a framework for mobile processes with nominal data and logic
The framework of psi-calculi extends the pi-calculus with nominal datatypes
for data structures and for logical assertions and conditions. These can be
transmitted between processes and their names can be statically scoped as in
the standard pi-calculus. Psi-calculi can capture the same phenomena as other
proposed extensions of the pi-calculus such as the applied pi-calculus, the
spi-calculus, the fusion calculus, the concurrent constraint pi-calculus, and
calculi with polyadic communication channels or pattern matching. Psi-calculi
can be even more general, for example by allowing structured channels,
higher-order formalisms such as the lambda calculus for data structures, and
predicate logic for assertions. We provide ample comparisons to related calculi
and discuss a few significant applications. Our labelled operational semantics
and definition of bisimulation is straightforward, without a structural
congruence. We establish minimal requirements on the nominal data and logic in
order to prove general algebraic properties of psi-calculi, all of which have
been checked in the interactive theorem prover Isabelle. Expressiveness of
psi-calculi significantly exceeds that of other formalisms, while the purity of
the semantics is on par with the original pi-calculus.Comment: 44 page
Matching Logic
This paper presents matching logic, a first-order logic (FOL) variant for
specifying and reasoning about structure by means of patterns and pattern
matching. Its sentences, the patterns, are constructed using variables,
symbols, connectives and quantifiers, but no difference is made between
function and predicate symbols. In models, a pattern evaluates into a power-set
domain (the set of values that match it), in contrast to FOL where functions
and predicates map into a regular domain. Matching logic uniformly generalizes
several logical frameworks important for program analysis, such as:
propositional logic, algebraic specification, FOL with equality, modal logic,
and separation logic. Patterns can specify separation requirements at any level
in any program configuration, not only in the heaps or stores, without any
special logical constructs for that: the very nature of pattern matching is
that if two structures are matched as part of a pattern, then they can only be
spatially separated. Like FOL, matching logic can also be translated into pure
predicate logic with equality, at the same time admitting its own sound and
complete proof system. A practical aspect of matching logic is that FOL
reasoning with equality remains sound, so off-the-shelf provers and SMT solvers
can be used for matching logic reasoning. Matching logic is particularly
well-suited for reasoning about programs in programming languages that have an
operational semantics, but it is not limited to this
The calculus of multivectors on noncommutative jet spaces
The Leibniz rule for derivations is invariant under cyclic permutations of
co-multiples within the arguments of derivations. We explore the implications
of this principle: in effect, we construct a class of noncommutative bundles in
which the sheaves of algebras of walks along a tesselated affine manifold form
the base, whereas the fibres are free associative algebras or, at a later
stage, such algebras quotients over the linear relation of equivalence under
cyclic shifts. The calculus of variations is developed on the infinite jet
spaces over such noncommutative bundles.
In the frames of such field-theoretic extension of the Kontsevich formal
noncommutative symplectic (super)geometry, we prove the main properties of the
Batalin--Vilkovisky Laplacian and Schouten bracket. We show as by-product that
the structures which arise in the classical variational Poisson geometry of
infinite-dimensional integrable systems do actually not refer to the graded
commutativity assumption.Comment: Talks given at Mathematics seminar (IHES, 25.11.2016) and Oberseminar
(MPIM Bonn, 2.02.2017), 23 figures, 60 page
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