Allen, Peter
(2007)
*Almost every 2-SAT function is unate.*
Israel Journal of Mathematics, 161
(1).
pp. 311-346.
ISSN 0021-2172

## Abstract

Bollob´as, Brightwell and Leader showed that there are at most 2^(n 2)+o(n2) 2-SAT functions on n variables, and conjectured that in fact the number of 2-SAT functions on n variables is 2^(n 2)+n(1 + o(1)). We prove their conjecture. As a corollary of this, we also find the expected number of satisfying assignments of a random 2-SAT function on n variables. We also find the next largest class of 2-SAT functions and show that if k = k(n) is any function with k(n) < n1/4 for all sufficiently large n, then the class of 2-SAT functions on n variables which cannot be made unate by removing 25k variables is smaller than 2(n 2)+n−kn for all sufficiently large n.

Item Type: | Article |
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Official URL: | http://www.springerlink.com/content/0021-2172/ |

Additional Information: | © 2007 Springer |

Library of Congress subject classification: | Q Science > QA Mathematics |

Sets: | Departments > Mathematics |

Rights: | http://www.lse.ac.uk/library/usingTheLibrary/academicSupport/OA/depositYourResearch.aspx |

Date Deposited: | 28 May 2012 15:10 |

URL: | http://eprints.lse.ac.uk/44103/ |

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