9 papers
The Complexity of Computing Class Probabilities in BID Probabilistic Databases
Sotiris Kanellopoulos, Ioannis Koutras, Aris Pagourtzis
We study the problem of computing class probabilities in block-independent disjoint (BID) probabilistic databases. Given the probability with which each block in the database reali…
Temporal Path Covers: Dilworth Properties and Parameterized Complexity
Lapo Cioni, Sotiris Kanellopoulos, Edouard Nemery +3
The Temporal Path Cover (TPC) and Temporally Disjoint Path Cover (TDPC) problems were introduced by [Chakraborty, Dailly, Foucaud, Klasing, MFCS '24] as the natural temporal analog…
Finite Pinwheel Covering
Sotiris Kanellopoulos
In perpetual scheduling theory, the Pinwheel Covering problem asks, given frequencies , whether there exists an infinite schedule such that every consecutive entries…
Hardness, Tractability and Density Thresholds of finite Pinwheel Scheduling Variants
Sotiris Kanellopoulos, Giorgos Mitropoulos, Christos Pergaminelis +1
The k-Visits problem is a recently introduced finite version of Pinwheel Scheduling [Kanellopoulos et al., SODA 2026]. Given the deadlines of n tasks, the problem asks whether ther…
EF(X) Orientations: A Parameterized Complexity Perspective
Sotiris Kanellopoulos, Edouard Nemery, Christos Pergaminelis +2
The concept of fair orientations in graphs was introduced by Christodoulou, Fiat, Koutsoupias, and Sgouritsa in 2023, naturally modeling fair division scenarios in which resources…
Finite Pinwheel Scheduling: the k-Visits Problem
Sotiris Kanellopoulos, Christos Pergaminelis, Maria Kokkou +2
Pinwheel Scheduling is a fundamental scheduling problem, in which each task is associated with a positive integer , and the objective is to schedule one task per time slot…
Beer Path Problems in Temporal Graphs
Andrea D'Ascenzo, Giuseppe F. Italiano, Sotiris Kanellopoulos +3
Computing paths in graph structures is a fundamental operation in a wide range of applications, from transportation networks to data analysis. The beer path problem, which captures…
Approximation Schemes for k-Subset Sum Ratio and k-way Number Partitioning Ratio
Sotiris Kanellopoulos, Giorgos Mitropoulos, Antonis Antonopoulos +5
The Subset Sum Ratio problem (SSR) asks, given a multiset of positive integers, to find two disjoint subsets of such that the largest-to-smallest ratio of their sums is min…
On the power of counting the total number of computation paths of NPTMs
Eleni Bakali, Aggeliki Chalki, Sotiris Kanellopoulos +2
In this paper, we define and study variants of several complexity classes of decision problems that are defined via some criteria on the number of accepting paths of an NPTM. In th…