6 papers
Size Bound-Adorned Datalog
Christian Fattebert, Zhekai Jiang, Christoph Koch +2
We introduce EDB-bounded datalog, a framework for deriving upper bounds on intermediate result sizes and the asymptotic complexity of recursive queries in datalog. We present an al…
From FPT Decision to FPT Enumeration
Nadia Creignou, Timo Camillo Merkl, Reinhard Pichler +1
Fixed-parameter tractable (FPT) algorithms have been successfully applied to many intractable problems -- with a focus on decision and optimization problems. Their aim is to confin…
The Space-Time Complexity of Sum-Product Queries
Kyle Deeds, Timo Camillo Merkl, Reinhard Pichler +1
While extensive research on query evaluation has achieved consistent improvements in the time complexity of algorithms, the space complexity of query evaluation has been largely ig…
Query Answering under Volume-Based Diversity Functions
Marcelo Arenas, Timo Camillo Merkl, Reinhard Pichler +1
When query evaluation produces too many tuples, a new approach in query answering is to retrieve a diverse subset of them. The standard approach for measuring the diversity of a se…
Towards Tractability of the Diversity of Query Answers: Ultrametrics to the Rescue
Marcelo Arenas, Timo Camillo Merkl, Reinhard Pichler +1
The set of answers to a query may be very large, potentially overwhelming users when presented with the entire set. In such cases, presenting only a small subset of the answers to…
Consistent Query Answering over SHACL Constraints
Shqiponja Ahmetaj, Timo Camillo Merkl, Reinhard Pichler
The Shapes Constraint Language (SHACL) was standardized by the World Wide Web as a constraint language to describe and validate RDF data graphs. SHACL uses the notion of shapes gra…