Hasse diagram

English

Etymology

Named after Helmut Hasse (1898–1979), though he was not the first to use them.

Noun

Hasse diagram (plural Hasse diagrams)

1. (set theory) A diagram which represents a finite poset, in which nodes are elements of the poset and arrows represent the order relation between elements. Transitivity of the order relation is tacit, in other words, if $x\leq y$ and $y\leq z$ then no arrow is drawn from x to z, but if there is no distinct z between x and y (such that $x\leq z\leq y$) then an arrow is draw from x to y.