1 code implementation • 28 Jan 2021 • Nikolaos Tziavelis, Wolfgang Gatterbauer, Mirek Riedewald
Our approach achieves strong time and space complexity properties: with $n$ denoting the number of tuples in the database, we guarantee for acyclic full join queries with inequality conditions that for every value of $k$, the $k$ top-ranked answers are returned in $\mathcal{O}(n \operatorname{polylog} n + k \log k)$ time.
Databases Data Structures and Algorithms
no code implementations • 22 Dec 2020 • Nofar Carmeli, Nikolaos Tziavelis, Wolfgang Gatterbauer, Benny Kimelfeld, Mirek Riedewald
For each of the two problems, we give a decidable characterization (under conventional complexity assumptions) of the class of tractable lexicographic orders for every CQ without self-joins.
Databases Data Structures and Algorithms
1 code implementation • NeurIPS 2019 • Nikolaos Tziavelis, Ioannis Giannakopoulos, Katerina Doka, Nectarios Koziris, Panagiotis Karras
Can a stable matching that achieves high equity among the two sides of a market be reached in quadratic time?
