scholarly journals A Dichotomy for the Generalized Model Counting Problem for Unions of Conjunctive Queries

2021 ◽  
Author(s):  
Batya Kenig ◽  
Dan Suciu
Keyword(s):  
Counting Problem ◽  
Generalized Model ◽  
Conjunctive Queries ◽  
Model Counting

scholarly journals The Model Counting Competition 2020

2021 ◽  
Vol 26 (1) ◽  
pp. 1-26
Author(s):  
Johannes K. Fichte ◽  
Markus Hecher ◽  
Florim Hamiti
Keyword(s):  
Practical Problem ◽  
Probabilistic Reasoning ◽  
Modern Society ◽  
Boolean Formula ◽  
Counting Problem ◽  
The Past ◽  
Boolean Formulas ◽  
Model Counting ◽  
Weighted Model ◽  
New Applications

Many computational problems in modern society account to probabilistic reasoning, statistics, and combinatorics. A variety of these real-world questions can be solved by representing the question in (Boolean) formulas and associating the number of models of the formula directly with the answer to the question. Since there has been an increasing interest in practical problem solving for model counting over the past years, the Model Counting Competition was conceived in fall 2019. The competition aims to foster applications, identify new challenging benchmarks, and promote new solvers and improve established solvers for the model counting problem and versions thereof. We hope that the results can be a good indicator of the current feasibility of model counting and spark many new applications. In this article, we report on details of the Model Counting Competition 2020, about carrying out the competition, and the results. The competition encompassed three versions of the model counting problem, which we evaluated in separate tracks. The first track featured the model counting problem, which asks for the number of models of a given Boolean formula. On the second track, we challenged developers to submit programs that solve the weighted model counting problem. The last track was dedicated to projected model counting. In total, we received a surprising number of nine solvers in 34 versions from eight groups.

scholarly journals The Dichotomy of Evaluating Homomorphism-Closed Queries on Probabilistic Graphs

2022 ◽  
Vol Volume 18, Issue 1 ◽  
Author(s):  
Antoine Amarilli ◽  
İsmail İlkan Ceylan
Keyword(s):  
Query Evaluation ◽  
Minimal Models ◽  
Conjunctive Queries ◽  
Complexity Dichotomy ◽  
Probabilistic Query ◽  
Regular Path ◽  
Regular Path Queries ◽  
Model Counting ◽  
Probabilistic Graphs ◽  
Path Queries

We study the problem of query evaluation on probabilistic graphs, namely, tuple-independent probabilistic databases over signatures of arity two. We focus on the class of queries closed under homomorphisms, or, equivalently, the infinite unions of conjunctive queries. Our main result states that the probabilistic query evaluation problem is #P-hard for all unbounded queries from this class. As bounded queries from this class are equivalent to a union of conjunctive queries, they are already classified by the dichotomy of Dalvi and Suciu (2012). Hence, our result and theirs imply a complete data complexity dichotomy, between polynomial time and #P-hardness, on evaluating homomorphism-closed queries over probabilistic graphs. This dichotomy covers in particular all fragments of infinite unions of conjunctive queries over arity-two signatures, such as negation-free (disjunctive) Datalog, regular path queries, and a large class of ontology-mediated queries. The dichotomy also applies to a restricted case of probabilistic query evaluation called generalized model counting, where fact probabilities must be 0, 0.5, or 1. We show the main result by reducing from the problem of counting the valuations of positive partitioned 2-DNF formulae, or from the source-to-target reliability problem in an undirected graph, depending on properties of minimal models for the query.

Cyclic and sequence-stratigraphic characteristics of the Vize-Serpukov deposits of the southern part of Moscow syncline

2018 ◽  
pp. 30-41
Author(s):  
R . R . Gabdullin ◽  
А. V. Bershov ◽  
Е. N. Samarin ◽  
N. V. Badulina ◽  
М. А. Afonin ◽  
...  
Keyword(s):  
Generalized Model ◽  
Sequence Stratigraphic ◽  
Biogenic Carbonate ◽  
Clastic Sediments

Composition and origin of Visean–Serpukhovian deposits of the Southern part of the Moscow syncline based upon generalizations of our own results and analysis of published and unpublished data were specified. The levels of karst-influenced rocks correspond to the shallowest biogenic carbonate organogeneous-clastic sediments of the initial and final phases of the eustatic cycle, i.e. the beginning of the transgression (the transgressive system of the tracts) and the end of the regression (the second half of the high-standing tract). In the karst cavities alluvial sands of the Oka river were found. A generalized model of the sequence was proposed and a sequential-stratigraphic interpretation of the studied section was carried out.

METHOD FOR ESTIMATING PARAMETERS OF GENERALIZED MODEL OF LUMINOSITY OF SPACE OBJECTS BASED ON DATA FROM DIFFERENT RANGES

2018 ◽  
pp. 57-62
Author(s):  
E. I. Gundrova ◽  
A. P. Lukyanov ◽  
A. V. Pruglo ◽  
S. S. Ravdin
Keyword(s):  
Phase Angle ◽  
Real Data ◽  
Model Data ◽  
Space Object ◽  
Distribution Law ◽  
Generalized Model ◽  
Measurement Results ◽  
Space Objects ◽  
Reference Distance

Previously, the authors have proposed a generalized model for estimating the distribution law parameters of luminosity of space objects, assuming that not only successful but also unsuccessful measurement results are taken into account. Estimation was done on the data of observations under similar conditions: phase angle, range, sensibility of the telescope. The algorithm under such limitations was tested on model data and real measurements. Therefore, obtained results showed that algorithm did not fit for cases of changing range of space objects. In this work, the new algorithm, that allows to merge information from different ranges to the observed space object, is proposed. In this case, luminosity values are reduced to the ones at a reference distance of 1000 km considering sensibility of the telescope. To obtain estimates of the parameters the Cramer-Mises-Smirnov criterion is used. This algorithm was tested on model data and results of its work on real data were obtained. The data showed correct work of the algorithm and also confirmed the practicability of organization the registration of unsuccessful measurements.

Responsibility Analysis for Lineages of Conjunctive Queries with Inequalities

2014 ◽  
Vol 26 (6) ◽  
pp. 1532-1543 ◽  
Author(s):  
Biao Qin ◽  
Shan Wang ◽  
Xiaofang Zhou ◽  
Xiaoyong Du
Keyword(s):  
Conjunctive Queries

scholarly journals Semantic Optimization in Tractable Classes of Conjunctive Queries

2017 ◽  
Vol 46 (2) ◽  
pp. 5-17 ◽  
Author(s):  
Pablo Barceló ◽  
Andreas Pieris ◽  
Miguel Romero
Keyword(s):  
Conjunctive Queries
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