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Gösta Grahne

Researcher at Concordia University

Publications -  80
Citations -  3644

Gösta Grahne is an academic researcher from Concordia University. The author has contributed to research in topics: Query language & Rewriting. The author has an hindex of 24, co-authored 79 publications receiving 3559 citations. Previous affiliations of Gösta Grahne include University of Helsinki & University of Toronto.

Papers
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Efficiently Using Prefix-trees in Mining Frequent Itemsets.

TL;DR: A novel array-based technique is presented that greatly reduces the need to traverse FP-trees, thus obtaining significantly improved performance for FPtree based algorithms, and works especially well for sparse datasets.
Journal ArticleDOI

Fast algorithms for frequent itemset mining using FP-trees

TL;DR: A novel FP-array technique is presented that greatly reduces the need to traverse FP-trees, thus obtaining significantly improved performance for FP-tree-based algorithms and works especially well for sparse data sets.
Journal ArticleDOI

On the representation and querying of sets of possible worlds

TL;DR: This work provides matching upper and lower bounds on the data-complexity of testing containment, membership and uniqueness for sets of possible worlds and shows that the certain fact problem is coNP-complete, even for a fixed first order query applied to a Codd-table.
Proceedings ArticleDOI

On the representation and querying of sets of possible worlds

TL;DR: The approach is algebraic but the authors' bounds also apply to logical databases, and it is shown that the approach is, in a sense, the best possible, by deriving two NP-completeness lower bounds for the bounded possible fact problem when the fixed query contains either negation or recursion.
Book

Problem of Incomplete Information in Relational Databases

Gösta Grahne
TL;DR: Relational databases.- Semantic aspects of incomplete information.- Syntactic and algorithmic aspects of complete information.- Computational complexity aspects ofcomplete information.