Monotone booleanfunctions (MBFs) are booleanfunctions f : {0, 1}(n) -> {0, 1} satisfying the monotonicity condition x <= y double right arrow f(x) <= f(y) for any x, y is an element of {0,1}(n)(.) The numbe...
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Monotone booleanfunctions (MBFs) are booleanfunctions f : {0, 1}(n) -> {0, 1} satisfying the monotonicity condition x <= y double right arrow f(x) <= f(y) for any x, y is an element of {0,1}(n)(.) The number of MBFs in n variables is known as the nth Dedekind number. It is a longstanding computational challenge to determine these numbers exactly: these values are only known for n at most 8. Two monotone booleanfunctions are equivalent if one can be obtained from the other by permuting the variables. The number of inequivalent MBFs in n variables was known only for up to n = 6. In this paper we propose a strategy to count inequivalent MBFs by breaking the calculation into parts based on the profiles of these functions. As a result we are able to compute the number of inequivalent MBFs in 7 variables. The number obtained is 490013148. (C) 2013 Elsevier B.V. All rights reserved.
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