We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Random graphs

https://cmi.ac.in/~madhavan/courses/verification-2011/alur-dill-tcs-94.pdf

A theory of timed automata

The 11th edition of Harrison's Principles of Internal Medicine welcomes Anthony Fauci to its editorial staff, in addition to more than 85 new contributors. While the organization of the book is similar to previous editions, major emphasis has been placed on disorders that affect multiple organ systems. Important advances in genetics, immunology, and oncology are emphasized. Many chapters of the book have been rewritten and describe major advances in internal medicine. Subjects that received only a paragraph or two of attention in previous editions are now covered in entire chapters. Among the chapters that have been extensively revised are the chapters on infections in the compromised host, on skin rashes in infections, on many of the viral infections, including cytomegalovirus and Epstein-Barr virus, on sexually transmitted diseases, on diabetes mellitus, on disorders of bone and mineral metabolism, and on lymphadenopathy and splenomegaly. The major revisions in these chapters and many

Harrison's Principles of Internal Medicine

The concept of an agent has become important in both Artificial Intelligence (AI) and mainstream computer science. Our aim in this paper is to point the reader at what we perceive to be the most important theoretical and practical issues associated with the design and construction of intelligent agents. For convenience, we divide these issues into three areas (though as the reader will see, the divisions are at times somewhat arbitrary). Agent theory is concerned with the question of what an agent is, and the use of mathematical formalisms for representing and reasoning about the properties of agents. Agent architectures can be thought of as software engineering models of agents;researchers in this area are primarily concerned with the problem of designing software or hardware systems that will satisfy the properties specified by agent theorists. Finally, agent languages are software systems for programming and experimenting with agents; these languages may embody principles proposed by theorists. The paper is not intended to serve as a tutorial introduction to all the issues mentioned; we hope instead simply to identify the most important issues, and point to work that elaborates on them. The article includes a short review of current and potential applications of agent technology.

/pdf/intelligent-agents-theory-and-practice-5dchj7p8pc.pdf

Intelligent Agents: Theory and Practice

/pdf/convex-analysisnoer-san-nojin-zhan-nituite-5dl2rbmoyr.pdf

Convex Analysisの二,三の進展について

One of the advantages of temporal-logic model-checking tools is their ability to accompany a negative answer to the correctness query by a counterexample to the satisfaction of the specification in the system. On the other hand, when the answer to the correctness query is positive, most model-checking tools provide no witness for the satisfaction of the specification. In the last few years there has been growing awareness to the importance of suspecting the system or the specification of containing an error also in the case model checking succeeds. The main justification of such suspects are possible errors in the modeling of the system or of the specification. Many such errors can be detected by further automatic reasoning about the system and the environment. In particular, Beer et al. described a method for the detection of vacuous satisfaction of temporal logic specifications and the generation of interesting witnesses for the satisfaction of specifications.

For example, verifying a system with respect to the specification Τ = AG(req → AF grant) ("every request is eventually followed by a grant"), we say that Τ is satisfied vacuously in systems in which requests are never sent. An interesting witness for the satisfaction of Τ is then a computation that satisfies Τ and contains a request. Beer et al. considered only specifications of a limited fragment of ACTL, and with a restricted interpretation of vacuity. In this paper we present a general method for detection of vacuity and generation of interesting witnesses for specifications in CTL*. Our definition of vacuity is stronger, in the sense that we check whether all the subformulas of the specification affect its truth value in the system. In addition, we study the advantages and disadvantages of alternative definitions of vacuity, study the problem of generating linear witnesses and counterexamples for branching temporal logic specifications, and analyze the complexity of the problem.

/pdf/vacuity-detection-in-temporal-model-checking-290v578apa.pdf

Vacuity Detection in Temporal Model Checking

The complexity of reasoning about knowledge and time

We systematically investigate the connections between constraint satisfaction problems, structures of bounded treewidth, and definability in logics with a finite number of variables. We first show that constraint satisfaction problems on inputs of treewidth less than k are definable using Datalog programs with at most k variables; this provides a new explanation for the tractability of these classes of problems. After this, we investigate constraint satisfaction on inputs that are homomorphically equivalent to structures of bounded treewidth. We show that these problems are solvable in polynomial time by establishing that they are actually definable in Datalog; moreover, we obtain a logical characterization of the property "being homomorphically equivalent to a structure of bounded treewidth" in terms of definability in finite-variable logics. Unfortunately, this expansion of the tractability landscape comes at a price, because we also show that, for each k ? 2, determining whether a structure is homomorphically equivalent to a structure of treewidth less than k is an NP-complete problem. In contrast, it is well known that, for each k ? 2, there is a polynomial-time algorithm for testing whether a given structure is of treewidth less than k. Finally, we obtain a logical characterization of the property "having bounded treewidth" that sheds light on the complexity-theoretic difference between this property andt he property 'being homomorphically equivalent to a structure of bounded treewidth".

http://www.cs.rice.edu/~vardi/papers/cp02.pdf

Constraint Satisfaction, Bounded Treewidth, and Finite-Variable Logics

"Thy destroyers and they that made thee waste shall go forth of thee," wrote the prophet Isaiah. This phrase has been popping into my mind as I have been following.

Will MOOCs destroy academia

Reasoning on queries is a basic problem both in knowledge representation and databases. A fundamental form of reasoning on queries is checking containment, i.e., verifying whether one query yields necessarily a subset of the result of another query. Query containment is crucial in several contexts, such as query optimization, knowledge base veriflcation, information integration, database integrity checking, and cooperative answering. In this paper we address the problem of query containment in the context of semistructured knowledge bases, where the basic querying mechanism, namely regular path queries, asks for all pairs of objects that are connected by a path conforming to a regular expression. We consider conjunctive regular path queries with inverse, which extend regular path queries with the possibility of using both the inverse of binary relations, and conjunctions of atoms, where each atom specifles that one regular path query with inverse holds between two variables. We present a novel technique to check containment of queries in this class, based on the use of two-way flnite automata. The technique shows the power of two-way automata in dealing with the inverse operator and with the variables in the queries. We also characterize the computational complexity of both the proposed algorithm and the problem.

/pdf/containment-of-conjunctive-regular-path-queries-with-inverse-3vltp5kj6p.pdf

Moshe Y. Vardi

Papers

Vacuity Detection in Temporal Model Checking

The complexity of reasoning about knowledge and time

Constraint Satisfaction, Bounded Treewidth, and Finite-Variable Logics

Will MOOCs destroy academia

Containment of Conjunctive Regular Path Queries with Inverse.