Yet another instance of graph theory before Euler's invention of the subject in 1736: https://plus.google.com/+JeffErickson/posts/TbsWRKnsC7R
(A few labeled graphs (with notes as vertices and intervals as edges), from the 1492 printing of Boethius's _De institutione musica_, posted by @jeffgerickson on Google+)
A Mastodon instance for maths people. The kind of people who make \(\pi z^2 \times a\) jokes.
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