Minimum about fuzzy logic
Treshold and majority function in binary logic

In the schoolbooks of logical systems design, majority and threshold functions are being used as illustrative examples for showing the process of design and minimization of logical expressions. Their logical value depends on the number of true operands and it remains the same for the given number for all combinations of operands - consequently these are ranked among symmetric functions. Threshold functions (“at least k from n” – denoted as f_k_n) are true if at least k (k or more) of the n operands equals to one. The number k is called threshold. Majority functions are the special case of threshold functions. They are defined for odd number of operands and they are true if more than a half (majority) of the operands are true.