(related to Chapter: Order Relations)
A Hasse diagram is a method named after Helmut Hasse (1898 - 1979), who used it to visualize a poset $(V,\preceq )$, which has only a finite number^{1} of elements. A Hasse diagram of a set $V$ can be drawn by applying the following rules:
As an example, consider the poset of the divisors of $24,$ i.e. the set $D:=\{1,2,3,4,6,8,12,24\}$ with the order $\prec:=\{(a,b)\in D\times D: a\mid b\}$. There are elements, which are incomparable (e.g. $3$ and $8$ since $3\not\mid 8$). Otherewise, there are many transitivities, e.g. $1 \mid 2$, $2\mid 4$, $4\mid 8$, and $8\mid 24$). To see the Hasse diagram, click on the Evaluate button below: §§§1
We will define later on what "finite" means in a strict mathematical manner. For the time being, it is sufficient to rely on the meaning of this word in the English language. ↩