19,712 research outputs found
Flexible Invariants Through Semantic Collaboration
Modular reasoning about class invariants is challenging in the presence of
dependencies among collaborating objects that need to maintain global
consistency. This paper presents semantic collaboration: a novel methodology to
specify and reason about class invariants of sequential object-oriented
programs, which models dependencies between collaborating objects by semantic
means. Combined with a simple ownership mechanism and useful default schemes,
semantic collaboration achieves the flexibility necessary to reason about
complicated inter-object dependencies but requires limited annotation burden
when applied to standard specification patterns. The methodology is implemented
in AutoProof, our program verifier for the Eiffel programming language (but it
is applicable to any language supporting some form of representation
invariants). An evaluation on several challenge problems proposed in the
literature demonstrates that it can handle a variety of idiomatic collaboration
patterns, and is more widely applicable than the existing invariant
methodologies.Comment: 22 page
Renormalization Invariants and Quark Flavor Mixings
A set of renormalization invariants is constructed using approximate,
two-flavor, analytic solutions for RGEs. These invariants exhibit explicitly
the correlation between quark flavor mixings and mass ratios in the context of
the SM, DHM and MSSM of electroweak interaction. The well known empirical
relations , can
thus be understood as the result of renormalization evolution toward the
infrared point. The validity of this approximation is evaluated by comparing
the numerical solutions with the analytical approach. It is found that the
scale dependence of these quantities for general three flavoring mixing follows
closely these invariants up to the GUT scale.Comment: 23 pages, 7 figure
PDDL2.1: An extension of PDDL for expressing temporal planning domains
In recent years research in the planning community has moved increasingly towards application of planners to realistic problems involving both time and many types of resources. For example, interest in planning demonstrated by the space research community has inspired work in observation scheduling, planetary rover ex ploration and spacecraft control domains. Other temporal and resource-intensive domains including logistics planning, plant control and manufacturing have also helped to focus the community on the modelling and reasoning issues that must be confronted to make planning technology meet the challenges of application. The International Planning Competitions have acted as an important motivating force behind the progress that has been made in planning since 1998. The third competition (held in 2002) set the planning community the challenge of handling time and numeric resources. This necessitated the development of a modelling language capable of expressing temporal and numeric properties of planning domains. In this paper we describe the language, PDDL2.1, that was used in the competition. We describe the syntax of the language, its formal semantics and the validation of concurrent plans. We observe that PDDL2.1 has considerable modelling power --- exceeding the capabilities of current planning technology --- and presents a number of important challenges to the research community
Prototyping Formal System Models with Active Objects
We propose active object languages as a development tool for formal system
models of distributed systems. Additionally to a formalization based on a term
rewriting system, we use established Software Engineering concepts, including
software product lines and object orientation that come with extensive tool
support. We illustrate our modeling approach by prototyping a weak memory
model. The resulting executable model is modular and has clear interfaces
between communicating participants through object-oriented modeling.
Relaxations of the basic memory model are expressed as self-contained variants
of a software product line. As a modeling language we use the formal active
object language ABS which comes with an extensive tool set. This permits rapid
formalization of core ideas, early validity checks in terms of formal invariant
proofs, and debugging support by executing test runs. Hence, our approach
supports the prototyping of formal system models with early feedback.Comment: In Proceedings ICE 2018, arXiv:1810.0205
On the impact of dimension-eight SMEFT operators on Higgs measurements
Using the production of a Higgs boson in association with a boson as a
test case, we assess the impact of dimension-8 operators within the context of
the Standard Model Effective Field Theory. Dimension-8--SM-interference and
dimension-6-squared terms appear at the same order in an expansion in
, hence dimension-8 effects can be treated as a systematic
uncertainty on the new physics inferred from analyses using dimension-6
operators alone. To study the phenomenological consequences of dimension-8
operators, one must first determine the complete set of operators that can
contribute to a given process. We accomplish this through a combination of
Hilbert series methods, which yield the number of invariants and their field
content, and a step-by-step recipe to convert the Hilbert series output into a
phenomenologically useful format. The recipe we provide is general and applies
to any other process within the dimension Standard Model Effective
Theory. We quantify the effects of dimension-8 by turning on one dimension-6
operator at a time and setting all dimension-8 operator coefficients to the
same magnitude. Under this procedure and given the current accuracy on
, we find the effect of dimension-8 operators on the
inferred new physics scale to be small, , with some
variation depending on the relative signs of the dimension-8 coefficients and
on which dimension-6 operator is considered. The impact of the dimension-8
terms grows as is measured more accurately or (more
significantly) in high-mass kinematic regions. We provide a FeynRules
implementation of our operator set to be used for further more detailed
analyses.Comment: More operator coefficient choices explored, bugs in FeynRules
implementation correcte
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