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A000372 Dedekind numbers or Dedekind's problem: number of monotone Boolean functions of n variables, number of antichains of subsets of an n-set, number of elements in a free distributive lattice on n generators, number of Sperner families.
(Formerly M0817 N0309)
30
2, 3, 6, 20, 168, 7581, 7828354, 2414682040998, 56130437228687557907788 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

A monotone Boolean function is an increasing functions from P(S), the set of subsets of S, to {0,1}.

The count of antichains includes the empty antichain which contains no subsets and the antichain consisting of only the empty set.

a(n) is also equal to the number of upsets of an n-set S. A set U of subsets of S is an upset if whenever A is in U and B is a superset of A then B is in U. - W. Edwin Clark, Nov 06 2003

Also the number of simple games with n players in minimal winning form. - Fabián Riquelme, May 29 2011

REFERENCES

I. Anderson, Combinatorics of Finite Sets. Oxford Univ. Press, 1987, p. 38.

J. L. Arocha, Antichains in ordered sets [in Spanish], Anales del Instituto de Matematicas de la Universidad Nacional Autonoma de Mexico, 27 (1987), 1-21.

Balbes, Raymond. On counting Sperner families. J. Combin. Theory Ser. A 27 (1979), no. 1, 1--9. MR0541338 (81b:05010) [From N. J. A. Sloane, Mar 19 2012]

J. Berman, ``Free spectra of 3-element algebras,'' in R. S. Freese and O. C. Garcia, editors, Universal Algebra and Lattice Theory (Puebla, 1982), Lect. Notes Math. Vol. 1004, 1983.

J. Berman and P. Koehler, Cardinalities of finite distributive lattices, Mitteilungen aus dem Mathematischen Seminar Giessen, 121 (1976), 103-124.

G. Birkhoff, Lattice Theory. American Mathematical Society, Colloquium Publications, Vol. 25, 3rd ed., Providence, RI, 1967, p. 63.

S. Bolus, A QOBDD-based Approach to Simple Games, Dissertation, Doktor der Ingenieurwissenschaften der Technischen Fakultaet der Christian-Albrechts-Universitaet zu Kiel, http://www.informatik.uni-kiel.de/~stb/files/diss_bolus.pdf, 2012. - From N. J. A. Sloane, Dec 22 2012

Donald E. Campbell, Jack Graver and Jerry S. Kelly, There are more strategy-proof procedures than you think, Mathematical Social Sciences 64 (2012) 263-265. - From N. J. A. Sloane, Oct 23 2012

Church, Randolph. Numerical analysis of certain free distributive structures. Duke Math. J. 6 (1940). 732--734. MR0002842 (2,120c) [According to Math Reviews, gives a(5) incorrectly as 7579]. - N. J. A. Sloane, Mar 19 2012

L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 273.

R. Dedekind, Über Zerlegungen von Zahlen durch ihre grössten gemeinsamen Teiler, Festschrift Hoch. Braunschweig u. ges. Werke(II), 1897, pp. 103-148.

E. N. Gilbert, Lattice theoretic properties of frontal switching functions, J. Math. Phys., 33 (1954), 57-67, see Table III.

M. A. Harrison, Introduction to Switching and Automata Theory. McGraw Hill, NY, 1965, p. 188.

J. Kahn, Entropy, independent sets and antichains, Entropy, independent sets and antichains: a new approach to Dedekind's problem, Proc. Amer. Math. Soc. 130 (2002), no. 2, 371-378.

D. J. Kleitman, On Dedekind's problem: The number of monotone Boolean functions. Proc. Amer. Math. Soc. 21 1969 677-682.

D. J. Kleitman and G. Markowsky, On Dedekind's problem: the number of isotone Boolean functions. II. Trans. Amer. Math. Soc. 213 (1975), 373-390.

D. E. Knuth, The Art of Computer Programming, Vol. 4A, Section 7.1.1, p. 79.

A. D. Korshunov, The number of monotone Boolean functions, Problemy Kibernet. No. 38, (1981), 5-108, 272. MR0640855 (83h:06013)

W. F. Lunnon, The IU function: the size of a free distributive lattice, pp. 173-181 of D. J. A. Welsh, editor, Combinatorial Mathematics and Its Applications. Academic Press, NY, 1971.

S. Muroga, Threshold Logic and Its Applications. Wiley, NY, 1971, p. 38 and 214.

R. A. Obando, On the number of nondegenerate monotone boolean functions of n variables in an n-variable boolean algebra. In preparation.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Tom Trotter, An Application of the Erdos/Stone Theorem, Sept. 13, 2001; http://people.math.gatech.edu/~trotter/slides/newhak.pdf

D. B. West, Introduction to Graph Theory, 2nd ed., Prentice-Hall, NJ, 2001, p. 349.

D. H. Wiedemann, A computation of the eighth Dedekind number, Order 8 (1991) 5-6.

LINKS

Table of n, a(n) for n=0..8.

K. S. Brown, Dedekind's problem

K. S. Brown, Asymptotic upper and lower bounds

Ori DAVIDOV and Shyamal PEDDADA, Order-Restricted Inference for Multivariate Binary Data With Application to Toxicology, Journal of the American Statistical Association, December 1, 2011, 106(496): 1394-1404, doi:10.1198/jasa.2011.tm10322

Patrick De Causmaecker and Stefan De Wannemacker, Partitioning in the space of anti-monotonic functions, arXiv:1103.2877.

Patrick De Causmaecker, Stefan De Wannemacker, On the number of antichains of sets in a finite universe, arXiv:1407.4288 [math.CO], 2014 (see Table 1).

Sylvain Guilley, Laurent Sauvage, Jean-Luc Danger, Tarik Graba, and Yves Mathieu, "Evaluation of Power-Constant Dual-Rail Logic as a Protection of Cryptographic Applications in FPGAs", SSIRI - Secure System Integration and Reliability Improvement, Yokohama: Japan (2008), pp 16-23, doi:10.1109/SSIRI.2008.31 [From Sylvain GUILLEY (Sylvain.Guilley(AT)TELECOM-ParisTech.fr), Aug 20 2009]

J. L. King, Brick tiling and monotone Boolean functions

R. A. Obando, Project: A map of a rule space.

Tamon Stephen and Timothy Yusun, Counting inequivalent monotone Boolean functions, arXiv preprint arXiv:1209.4623, 2012

Eric Weisstein's World of Mathematics, Antichain

R. Zeno, A007501 is an upper bound

Index entries for sequences related to Boolean functions

FORMULA

The asymptotics can be found in the Korshunov paper. - Boris Bukh, Nov 07 2003

a(n) = Sum_{k=1..n} binomial(n,k)*A006126(k) + 2, i.e., this sequence is the inverse binomial transform of A006126, plus 2. E.g. a(3) = 3*1 + 3*2 + 1*9 + 2 = 20. - Rodrigo A. Obando (R.Obando(AT)computer.org), Jul 26 2004

EXAMPLE

a(2)=6 from the antichains {}, {{}}, {{1}}, {{2}}, {{1,2}}, {{1},{2}}.

CROSSREFS

Equals A014466 + 1, also A007153 + 2. Cf. A003182, A059119.

Sequence in context: A176806 A168268 A002078 * A123930 A238895 A125601

Adjacent sequences:  A000369 A000370 A000371 * A000373 A000374 A000375

KEYWORD

nonn,hard,more,nice

AUTHOR

N. J. A. Sloane.

EXTENSIONS

a(8) from D. H. Wiedemann, personal communication, circa 1990.

Additional comments from Michael Somos, Jun 10 2002

STATUS

approved

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Last modified August 2 04:43 EDT 2014. Contains 245138 sequences.