The  A003182(4) = 30 inequivalent of monotonic 4-ary Boolean functions ordered in a Hasse diagram

This is a selection of the Dedekind(4) = 168 monotonic functions, with each big equivalence class (BEC) represented by one of its functions.

The function chosen as the representator of its BEC is the one with the lowest ring count vector (RCV). The lowest RCV is unique for all BECs except three with weights between 7 and 9: In BEC 297 and its complement 312 all three functions have the same RCV. In the self-complementary BEC 203 two of the twelve functions have the lowest RCV. (Compare this list.) The possible representators of these BECs are shown in the bottom right corner.

In this Hasse diagram there is an arrow between the BECs ${\displaystyle A}$ and ${\displaystyle B}$ if there is an ${\displaystyle a\in A}$ and a ${\displaystyle b\in B}$ such that ${\displaystyle a\rightarrow b}$.
Generally this relation exists between the chosen representators, exept for the three knots mentioned above.
For those with weight 7 and 9 the middle representator is chosen, so that the arrows to the lower (333→297) and from the upper (312→346) look intuitive, but not the arrows between them (297→203 and 203→312). For that with weight 8 the right representator is chosen, so the arrow from below looks intuitive (77→203) but not that to the right (203→92).

The index numbers refer to the rational order of BECs.

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