Abstract
An n-ary relation ρ on a set U is strongly rigid if it is preserved only by trivial operations. It is projective if the only idempotent operations in P o l ρ are projections. Rosenberg, (Rocky Mt. J. Math. 3, 631–639, 1973) characterized all strongly rigid relations on a set with two elements and found a strongly rigid binary relation on every domain U of at least 3 elements. Larose and Tardif (Mult.-Valued Log. 7(5-6), 339–362, 2001) studied the projective and strongly rigid graphs and constructed large families of strongly rigid graphs. Łuczak and Nešetřil (J. Graph Theory. 47, 81–86, 2004) settled in the affirmative a conjecture of Larose and Tardif that most graphs on a large set are projective, and characterized all homogenous graphs that are projective. Łuczak and Nešetřil (SIAM J. Comput. 36(3), 835–843, 2006) confirmed a conjecture of Rosenberg that most relations on a big set are strongly rigid. In this paper, we characterize all strongly rigid relations on a set with at least three elements to answer an open question by Rosenberg, (Rocky Mt. J. Math. 3, 631–639, 1973) and we classify the binary relations on the 4-element domain by rigidity and demonstrate that there are merely 40 pairwise nonisomorphic rigid binary relations on the same domain (among them 25 are pairwise nonisomorphic strongly rigid).
Similar content being viewed by others
References
Post, E.L.: The two-valued iterative system of mathematical logic, Annals of Mathematical Studies 5, pp 1–122. Princeton University Press (1941)
Swierczkowski, S.: Algebras which are independently generated by every n elements. Fund. Math. 49, 93–104 (1960)
Geiger, D.: Closed systems of functions and predicates. Pacific J. Math. 27, 95–100
Bodnarčuk, V.G., Kalužhnin, L.A., Kotov, V.N., Romov, B.A.: Galois theory for Post algebras I-II, Kibernetika, 3 (1969), pp. 1–10 and 5 (1969), pp. 1–9 (in Russian); Cybernetics, (1969), pp. 243–252, 531–539 (English version), 1969
Rosenberg, I.G.: Strongly rigid relations. Rocky Mt. J. Math. 3, 631–639 (1973)
Schaefer, T.J.: The complexity of the satisfiability problems. Proc. 10th ACM Symp. Theory Comput. (STOC) 15, 216–226 (1978)
Csákány, B.: All minimal clones on the three element set. Acta Cybernet. 6, 227–238 (1983)
Rosenberg, I.G.: Minimal clones I: the five types, Lectures in universal algebra (Szeged, 1983). Colloquia Mathematical Society Janos Bolyai, Janos Bolyai, 43, North-Holland, Amsterdam, 1986, pp. 405–427
Szendrei, Á.: Clones in Universal Algebra. Presses de l’Université de Montréal, Montreal (1986)
Bang-Jensen, J., Hell, P.: The effect of two cycles on the complexity of colourings by directed graphs. Discret. Appl. Math. 26(1), 1–23 (1990)
Szczepara, B.: Minimal Clones Generated by Groupoids. Ph.D. Thesis, Université de Montréal, Montréal (1995)
Fearnley, A.: A strongly rigid binary relation. Acta Sci. Math. (Szeged) 61, 35–41 (1995)
Berman, J., Burris, S.: A computer study of 3-element groupoids. In: Logic and Algebra (Pontignano, 1994), Lecture Notes in Pure and Applied Mathematics, 180, pp 379–429, Dekker (1996)
Feder, T., Vardi, M.Y.: The computational structure of monotone monadic SNP and constraint satisfaction: A study through Datalog and group theory. SIAM J. Comput. 28(1), 57–104 (1998)
Jeavons, P.G.: On the algebraic structure of combinatorial problems. Theor. Comput. Sci. 200, 185–204 (1998)
Bulatov, A., Jeavons, P., Krokhin, A.: Constraint satisfaction problems and finite algebras. In: Proceedings of 27th International Colloquim on Automata, Languages and Programming (ICALP00), vol. 1853, pp 272–282. Lecture Notes in Computer Science, Geneva, Switzerland (2000)
Larose, B., Tardif, C.: Strongly rigid graphs and projectivity. Mult.-Valued Log. 7(5-6), 339–362 (2001)
Bulatov, A., Jeavons, P., Krokhin, A.: The complexity of maximal constraint languages. In: Proceedings of the 33rd Annual ACM Simposium on Theory of Computing, pp 667–674. ACM Press, Crete, Greece (2001)
Łuczak, T., Nešetřil, J.: A note on projective graphs. J. Graph Theory 47, 81–86 (2004)
Csákány, B.: Minimal clones a minicourse. Algebra Univ. 54, 73–89 (2005)
Larose, B.: Taylor operations on finite reflexive structures. Int. J. Math. Comput. Sci. 1(1), 1–26 (2006)
Łuczak, T., Nešetřil, J.: A probabilistic approach to the dichotomy problem. SIAM J. Comput. 36(3), 835–843 (2006)
Larose, B., Tesson, P.: Universal algebra and hardness results for constraint satisfaction problems. Theor. Comput. Sci. 410(18), 1629–1647 (2009)
Barto, L., Kozik, M., Niven, T.: The CSP dichotomy holds for digraphs with no sources and no sinks (a positive answer to a conjecture of Bang-Jensen and Hell). SIAM J. Comput. 38(5), 1782–1802 (2009)
Barto, L., Kozik, M.: Constraint satisfaction problems of bounded width. In: Proceedings of the 50th Annual IEEE Symposium on Foundations of Computer Science, pp 595–603 (2009)
Barto, L., Stanovský, D.: Polymorphisms of small digraphs. Novi. Sad J. Math. 2(40), 95–109 (2010)
Machida, H., Rosenberg, I.G. Centralizing Monoids on a Three-Element Set: 2012 IEEE 42nd International Symposium on Multiple-Valued Logic, pp 274–280
Kazda, A.: Complexity of the homomorphism extension problem in the random case. Chic. J. Theor. Comput. Sci. 2013(9) (2013)
Jovanović, J.: On optimal strong Mal’cev conditions for congruence meet-semidistributivity in a locally finite variety. Novi Sad J. Math. 44(2), 207–224 (2014)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Sun, Q. Rigid Binary Relations on a 4-Element Domain. Order 34, 165–183 (2017). https://doi.org/10.1007/s11083-016-9394-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11083-016-9394-z