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09:00-10:15 Session 64E: Welcome and Invited Talk
Location: FH, Seminarraum 104
SMT: Where do we go from here?
SPEAKER: Clark Barrett

ABSTRACT. There is no question that the last decade has been a remarkable success story for SMT. Yet,

many challenges remain that are obstacles to unlocking the full potential of this technology. In

this talk, I will take a look at what has brought SMT to this point, including some notable

success stories. Then I will discuss some of the remaining challenges, both technical and non-

technical, and suggest directions for addressing these challenges.


10:15-10:45Coffee Break
10:45-13:00 Session 66AT: Program Analysis and Sets
Location: FH, Seminarraum 104
Speeding Up SMT-Based Quantitative Program Analysis

ABSTRACT. Quantitative program analysis involves computing numerical quantities about individual or collections of program executions. An example of such a computation is quantitative information flow analysis, where one estimates the amount of information leaked about secret data through a program's output channels. Such information can be quantified in several ways, including channel capacity and (Shannon) entropy. In this paper, we formalize a class of quantitative analysis problems defined over a weighted control flow graph of a program. These problems can be solved using a combination of path enumeration, SMT solving, and model counting. However, existing methods can only handle very small programs, primarily because the number of execution paths can be exponential in the program size. We show how path explosion can be mitigated in some practical cases by taking advantage of special branching structure and by novel algorithm design. We demonstrate our techniques by computing the channel capacities of the timing side-channels of two programs with extremely large numbers of paths.

Multi-solver Support in Symbolic Execution
SPEAKER: unknown

ABSTRACT. In this talk, we will present the results reported in our CAV 2013 paper on integrating support for multiple SMT solvers in the dynamic symbolic execution engine KLEE. In particular, we will outline the key characteristics of the SMT queries generated during symbolic execution, introduce an extension of KLEE that uses a number of state-of-the-art SMT solvers (Z3, Boolector and STP) through the metaSMT solver framework, and compare the solvers' performance when run on large sets of QF_ABV queries obtained during the symbolic execution of real-world software. In addition, we will discuss several options for designing a parallel portfolio solver for symbolic execution tools.

Protocol log analysis with constraint programming
SPEAKER: unknown

ABSTRACT. Testing a telecommunication protocol often requires protocol log analysis. A protocol log is a sequence of messages with timestamps. Protocol log analysis involves checking that the content of messages and timestamps are correct with respect to the protocol specification. We model the protocol specification using constraint programming (MiniZinc), and we present an approach where a constraint solver is used to perform protocol log analysis. Our case study is the Public Warning System service, which is a part of the Long Term Evolution (LTE) 4G standard.

Reasoning About Set Comprehensions

ABSTRACT. Set comprehension is a mathematical notation for defining sets on the basis of a property of their members. Although set comprehension is widely used in mathematics and some programming languages, direct support for reasoning about it is still not readily available in state-of-the-art SMT solvers. This paper presents a technique for translating formulas which express constraints involving set comprehensions into first-order formulas that can be verified by off-the-shelf SMT solvers. More specifically, we have developed a lightweight Python library that extends the popular Z3 SMT solver with the ability to reason about the satisfiability of set comprehension patterns. This technique is general and can be deployed in a broad range SMT solvers.

13:00-14:30Lunch Break
14:30-16:00 Session 75AU: Arrays and Polymorphism
Location: FH, Seminarraum 104
Weakly Equivalent Arrays
SPEAKER: unknown

ABSTRACT. The (extensional) theory of arrays is widely used to model systems. Hence, efficient decision procedures are needed to model check such systems. Current decision procedures for the theory of arrays saturate the read-over-write and extensionality axioms originally proposed by McCarthy. Various filters are used to limit the number of axiom instantiations while preserving completeness. We present an algorithm that lazily instantiates lemmas based on weak equivalence classes. These lemmas are easier to interpolate as they only contain existing terms. We formally define weak equivalence and show correctness of the resulting decision procedure.

Decision Procedures for Flat Array Properties

ABSTRACT. We present new decidability results for quantified fragments of theories of arrays. Our decision procedures are fully declarative, parametric in the theories of indexes and elements and orthogonal with respect to known results. We also discuss applications to the analysis of programs handling arrays.

Extending SMT-LIB v2 with lambda-terms and polymorphism
SPEAKER: unknown

ABSTRACT. This paper describes two syntactic extensions to SMT-LIB proof scripts: lambda-expressions and polymorphism. After extending the syntax to allow these expressions, we show how to update the typing rules of the SMT-LIB to check the validity of these new terms and commands. Since most SMT-solvers only deal with many-sorted first-order formulas, we detail a monomorphization mechanism to allow to use polymorphism in SMT-LIB syntax while retaining a monomorphic solver core.

16:00-16:30Coffee Break
16:30-19:00 Session 79A: VSL Joint Award Ceremony 1
Location: MB, Kuppelsaal
Foundations and Technology Competitions Award Ceremony

ABSTRACT. The third round of the Kurt Gödel Research Prize Fellowships Program, under the title: Connecting Foundations and Technology, aims at supporting young scholars in early stages of their academic careers by offering highest fellowships in history of logic, kindly supported by the John Templeton Foundation. Young scholars being less or exactly 40 years old at the time of the commencement of the Vienna Summer of Logic (July 9, 2014) will be awarded one fellowship award in the amount of EUR 100,000, in each of the following categories:

  • Logical Foundations of Mathematics,
  • Logical Foundations of Computer Science, and
  • Logical Foundations of Artificial Intelligence

The following three Boards of Jurors were in charge of choosing the winners:

  • Logical Foundations of Mathematics: Jan Krajíček, Angus Macintyre, and Dana Scott (Chair).
  • Logical Foundations of Computer Science: Franz Baader, Johann Makowsky, and Wolfgang Thomas (Chair).
  • Logical Foundations of Artificial Intelligence: Luigia Carlucci Aiello, Georg Gottlob (Chair), and Bernhard Nebel.


FLoC Olympic Games Award Ceremony 1

ABSTRACT. The aim of the FLoC Olympic Games is to start a tradition in the spirit of the ancient Olympic Games, a Panhellenic sport festival held every four years in the sanctuary of Olympia in Greece, this time in the scientific community of computational logic. Every four years, as part of the Federated Logic Conference, the Games will gather together all the challenging disciplines from a variety of computational logic in the form of the solver competitions.

At the Award Ceremonies, the competition organizers will have the opportunity to present their competitions to the public and give away special prizes, the prestigious Kurt Gödel medals, to their successful competitors. This reinforces the main goal of the FLoC Olympic Games, that is, to facilitate the visibility of the competitions associated with the conferences and workshops of the Federated Logic Conference during the Vienna Summer of Logic.

This award ceremony will host the

  • 3rd Confluence Competition (CoCo 2014);
  • Configurable SAT Solver Challenge (CSSC 2014);
  • Ninth Max-SAT Evaluation (Max-SAT 2014);
  • QBF Gallery 2014; and
  • SAT Competition 2014 (SAT-COMP 2014).
FLoC Closing Week 1
SPEAKER: Helmut Veith