# Hasse diagram

## English[edit]

### Etymology[edit]

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

### Noun[edit]

**Hasse diagram** (*plural* **Hasse diagrams**)

- (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 and then no arrow is drawn from
*x*to*z*, but if there is no distinct*z*between*x*and*y*(such that ) then an arrow is draw from*x*to*y*.