For readers who aren’t super familiar with graph theory and Hasse diagrams, fast and loose use of the word ‘line’ by itself might be confusing (since everything looks like a line). For example, on line 11, ‘line’ is used to refer to an arrow in a diagram, and I think line 5 uses ‘line’ to mean ‘edge’. IMHO it would be nice to do a little bit of hand-holding and say line of text for the first paragraph or two, and explicitly saw ‘arrow’ and ‘edge’ where appropriate. The patch I’m about to push assumes the author’s intent on line 5 was changes may introduce both vertices and edges, since the first model equates vertices with lines of text, and the verb introduce is used with edges later in the document.

Thanks, some of these were indeed pretty confusing. Feel free to send more fixes if you like, this is really appreciated.