We investigate new approaches for frequent graph-based pattern mining in graph datasets and propose a novel algorithm called gSpan (graph-based Substructure pattern mining), which discovers frequent substructures without candidate generation. gSpan builds a new lexicographic order among graphs, and maps each graph to a unique minimum DFS code as its canonical label. Based on this lexicographic ...

We show that graphs generated by collapsible pushdown systems of level 2 are tree-automatic. Even if we allow ε-contractions and reachability predicates (with regular constraints) for pairs of configurations, the structures remain tree-automatic whence their first-order logic theories are decidable. As a corollary we obtain the tree-automaticity of the second level of the Caucal-hierarchy.

Let α be an infinite ordinal. There are non-isomorphic representable algebras of dimension α each of which is a generating subreduct of the same β dimensional algebra. Dually there exists a representable algebra A of dimension , α such that A is a generating subreduct of B and , B′ however, B and B′ are not isomorphic. The above was proven to hold for infinite dimensional cylindric algebras (CA...

Complete checks of database integrity constraints may be prohibitively time consuming, and several methods have been suggested for producing simplified checks for each update. The present approach introduces a set of transformation operators that apply to database integrity constraints with each operator representing a concise, semanticspreserving operation. These operators are applied in a pro...

This article discusses some properties of the rst order regression method for imputation of missing values on an explanatory variable in linear regression model and presents an estimation strategy based on hypothesis testing.

Probabilistic databases store, query and manage large amounts of uncertain information in an efficient way. This paper summarizes my thesis which advances the state-of-the-art in probabilistic databases in three different ways: First, we present a closed and complete data model for temporal probabilistic databases. Queries are posed via temporal deduction rules which induce lineage formulas cap...

A data tree is a tree where each node has a label from a finite set, and a data value from a possibly infinite set. We consider data trees whose depth is bounded beforehand. By developing an appropriate automaton model, we show that under this assumption various formalisms, including a two variable first-order logic and a subset of XPath, have decidable emptiness problems.

In the article of 1965 Are logical truths analytic? Hintikka deals with the problem of establishing whether the logical truths of first-order logic are analytic or synthetic. In order to provide an answer to this issue, Hintikka firstly distinguishes two different notions of analyticity, and then he shows that the sentences of first-order logic are analytic in one sense, but synthetic in anothe...

Spatial logics are used to reason locally about disjoint data structures. They consist of standard first-order logic constructs, spatial (structural) connectives and their corresponding adjuncts. Lozes has shown that the adjuncts add no expressive power to a spatial logic for analysing tree structures, a surprising and important result. He also showed that a related logic does not have this adj...

Sequence logic is a parameterized logic where the formulas are sequences of formulas of some arbitrary underlying logic. The sequence formulas are interpreted in certain linearly ordered sets of models of the underlying logic. This interpretation induces an entailment relation between sequence formulas which strongly depends on which orderings one wishes to consider. Some important classes are:...