Główne pojęcia
This paper presents the first monitoring algorithm for the expressive class of second-order hyperproperties, which can capture complex system properties like common knowledge that cannot be expressed in first-order logics.
Streszczenie
The paper introduces Hyper2LTL𝑓, a temporal logic that extends HyperLTL with second-order quantification over sets of traces. It studies the monitoring problem in two execution models: the parallel model with a fixed number of traces, and the sequential model with an unbounded number of traces observed one by one.
For the parallel model, the authors show that monitoring second-order hyperproperties can be reduced to monitoring first-order hyperproperties. For the sequential model, they present a monitoring algorithm that handles second-order quantification efficiently by exploiting optimizations based on monotonicity of subformulas, graph-based storing of executions, and fixpoint hashing.
The algorithm has been implemented in a tool called MoSo and evaluated on several benchmarks, including examples from common knowledge and planning.
Statystyki
Monitoring second-order hyperproperties is undecidable in the sequential model in general.
The authors identify a practically relevant class of monotone second-order hyperproperties that can be monitored effectively.
Experimental results on benchmarks show the feasibility of the proposed monitoring approach.
Cytaty
"Hyperproperties express the relationship between multiple executions of a system. This is needed in many AI-related fields, such as knowledge representation and planning, to capture system properties related to knowledge, information flow, and privacy."
"Second-order hyperproperties include system properties like common knowledge, which cannot be expressed in first-order logics like HyperLTL."