A sum-free set
is a set for which the intersection of and the sumset is empty.
For example, the sum-free sets of are , , ,
, , and . The numbers of sum-free subsets of for , 1, ... are 1, 2, 3, 6, 9, 16, 24, 42, 61, ... (OEIS A007865 ).
The numbers of sum-free sets can be computed in the Wolfram Language using the following code (P. Abbott, pers. comm., Nov. 24,
2005):
NumbersOfSumFreeSets[nmax_] := Module[{n = 0},
Last[Reap[Nest[(++n; Sow[Length[#]];
Union[#, Union[#, {n}]& /@
Select[#, Intersection[#, n - #] == {}&]])&,
{{}}, nmax + 1]
]
]
]
See also A-Sequence ,
Cameron's Sum-Free Set Constant ,
Double-Free Set ,
Hofstadter Sequences ,
Prime
Number of Measurement ,
s -Additive Sequence,
Schur Number ,
Schur's
Problem ,
Stöhr Sequence ,
Triple-Free
Set
Explore with Wolfram|Alpha
References Abbott, H. L. and Moser, L. "Sum-Free Sets of Integers." Acta Arith. 11 , 392-396, 1966. Cameron,
P. J. and Erdős, P. "On the Number of Sets of Integers with Various
Properties." Number
Theory. Proceedings of the First Conference of the Canadian Number Theory Association
held in Banff, Alberta, April 17-27, 1988 (Ed. R. A. Mollin). Berlin:
de Gruyter, pp. 61-79, 1990. Cameron, P. J. and Erdős,
P. "Notes on Sum-Free and Related Sets." Combin. Probab. Comput. 8 ,
95-107, 1999. Exoo, G. "A Lower Bound for Schur Numbers and Multicolor
Ramsey Numbers of ."
Electronic J. Combinatorics 1 , No. 1, R8, 1-3, 1994. http://www.combinatorics.org/Volume_1/Abstracts/v1i1r8.html . Finch,
S. R. "Cameron's Sum-Free Set Constants." §2.25 in Mathematical
Constants. Cambridge, England: Cambridge University Press, pp. 180-183,
2003. Fredricksen, H. and Sweet, M. M. "Symmetric Sum-Free
Partitions and Lower Bounds for Schur Numbers." Electronic J. Combinatorics 7 ,
No. 1, R32, 1-9, 2000. http://www.combinatorics.org/Volume_7/Abstracts/v7i1r32.html . Green,
B. "The Cameron-Erdős Conjecture." Apr. 4, 2003. http://www.arxiv.org/abs/math.NT/0304058/ . Sloane,
N. J. A. Sequence A007865 in "The
On-Line Encyclopedia of Integer Sequences." Wallis, W. D.;
Street, A. P.; and Wallis, J. S. Combinatorics:
Room Squares, Sum-free Sets, Hadamard Matrices. New York: Springer-Verlag,
1972. Wang, E. T. H. "On Double-Free Sets of Integers."
Ars Combin. 28 , 97-100, 1989. Referenced on Wolfram|Alpha Sum-Free Set
Cite this as:
Weisstein, Eric W. "Sum-Free Set." From
MathWorld --A Wolfram Web Resource. https://mathworld.wolfram.com/Sum-FreeSet.html
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