We present a novel algorithm to compute large itemsets online. The user is free to change the support threshold any time during the first scan of the transaction sequence. The algorithm maintains a superset of all large itemsets and for each itemset a shrinking, deterministic interval on its support. After at most 2 scans the algorithm terminates with the… (More)
Proefschrift voorgelegd tot het behalen van de graad van Doctor in de Wetenschappen, richting Informatica te verdedigen door Acknowledgements Many people have contributed to the realization of this thesis. First an foremost, I am grateful to my advisor Jan Van den Bussche for his guidance throughout my doctoral studies and all the time and effort he put in… (More)
We show that the isoperimetric function of a nitely generated nilpotent group of class c is bounded above by a polynomial of degree 2c.
51 Interactive Data Analysis: The Control Project D ata analysis is fundamentally an iterative process in which you issue a query, receive a response, formulate the next query based on the response, and repeat. You usually don't issue a single, perfectly chosen query and get the information you want from a database; indeed, the purpose of data analysis is… (More)
We consider amalgamations of nitely generated nilpotent groups of class c. We show that doubles satisfy a polynomial isoperimetric inequality of degree 2c 2. Generalising doubles we i n troduce non-twisted amalgamations and show that they satisfy a polynomial isoperimetric inequality a s w ell. We give a suucient condition for amalgamations along abelian… (More)
We show that amalgams of nitely generated torsionfree nilpotent groups of class c along a cyclic subgroup satisfy a polynomial isoperi-metric inequality of degree 4c 2. The distortion of the amalgamated subgroup is bounded above by a polynomial of degree c. We also give an example of a non-cyclic amalgam of nitely generated torsion-free nilpotent groups… (More)
We present a n i n tegration of Mathematica into Prolog using MathLink. We illustrate the interplay b e t w een the diierent components by e v aluating a simple example. The motivation based on algebraic modeling as well as an application from combina-torial group theory are brieey sketched.