@InProceedings{martin_et_al:DagSemProc.09441.5,
author = {Martin, Barnaby and Martin, Jos},
title = {{The complexity of positive first-order logic without equality II: The four-element case}},
booktitle = {The Constraint Satisfaction Problem: Complexity and Approximability},
pages = {1--12},
series = {Dagstuhl Seminar Proceedings (DagSemProc)},
ISSN = {1862-4405},
year = {2010},
volume = {9441},
editor = {Andrei A. Bulatov and Martin Grohe and Phokion G. Kolaitis and Andrei Krokhin},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/DagSemProc.09441.5},
URN = {urn:nbn:de:0030-drops-23670},
doi = {10.4230/DagSemProc.09441.5},
annote = {Keywords: Quantified constraints, Galois connection}
}