Categories
  Encyclosphere.org ENCYCLOREADER
  supported by EncyclosphereKSF

Gender of Boolean functions

From Wikiversity - Reading time: 5 min

Studies of Boolean functions
gender ratio for arities 0...5

A Boolean function shall be called male, iff its root is sharp (i.e. iff its compressed truth table has odd weight).
(Equivalently, it is female, iff after removing all repetitions, the weight of the truth table is still even.)

For positive arities, there are more males than females. The imbalance peaks for arity 2. For higher arities, the ratio is almost balanced.
The ratio is balanced for the infinite set of all Boolean functions. Both sets are countable, so there is a trivial bijection. But is there a meaningful bijection?

The number triangles in the following boxes show the numbers of Boolean functions by arity/adicity and valency.
Row indices on the left (🌊) are the arity, on the right (💧) the adicity. Entries on the left are the sums of columns on the right.
These triangles are based on Pascals triangle, with columns multiplied by consecutive entries of a sequence, which becomes the diagonal.








honesty and gender

[edit | edit source]

The XOR of all members of a family is either the tautology or the contradiction. Where it is the tautology, the BF shall be called honest.
Apparently there are no dishonest males. So every dishonest BF is female, and every male BF is honest. (It should be kept in mind, that these are statements about Boolean functions. Generally, it is discouraged to assume, that all males are honest.)

See triangles by weight, e.g. male, honest.

The following images show 3-ary Boolean functions.   See also: Boolf prop/3-ary/honesty and gender, Boolf prop/3-ary/honesty, gender, sharpness, introversion
The pattern of Zhegalkin indices for dishonest BF is similar to a Walsh matrix (with columns 3 and 7 exchanged). But that is specific to arity 3. So is the fact, that all non-trivial dishonest BF are balanced.


Licensed under CC BY-SA 3.0 | Source: https://en.wikiversity.org/wiki/Gender_of_Boolean_functions
16 views | Status: cached on August 14 2025 18:13:54
↧ Download this article as ZWI file
Encyclosphere.org EncycloReader is supported by the EncyclosphereKSF