Scott Fleischmann wrote:

> What is the motivation for the authors to use a non-standard definition of poset (and moreover, not call it out as non-standard in the text)?

They're evil. They're trying to spread confusion and destroy mathematics. They're funded by Putin and they're working for Cambridge Analytica.

Seriously, as Dan Schmidt suggests in 62, they believe - correctly! - that posets are less fundamental than preorders. However, I think it's misguided for them to tackle this by renaming preorders "posets". They should either call them "preorders", like everyone else does, or make up some brand new term if they think "preorder" is too ugly.