One of the recent big and, in my view, underappreciated innovations in the field of Qualitative Comparative Analysis (QCA) is Baumgartner’s formulation of the Coincidence Analysis algorithm (CNA). Baumgartner presents it as an alternative to QCA, which I do not find convincing because I do not see QCA married to a specific algorithm.

It's a nice feeling when work that one did ages ago seems relevant again. Markus Döring has been working on a new backbone classification of all the species which occur in taxonomic checklists harvested by GBIF. After building a new classification the obvious question arises "how does this compare to the previous GBIF classification?" A simple question, answering it however is a little tricky.

I have an "on again/off again" relationship with treemaps. Lately, I've been taking another look, partly inspired by Björn Engdahl's MSc thesis Ordered and Unordered Treemap Algorithms and Their Applications on Handheld Devices.

Quick note to self, having stumbled on the Wikipedia page on transitive reduction. Given a graph like this:the transitive reduction is:Note that the original graph has an edge a -> d, but this is absent after the reduction because we can get from a to d via b (or c). What's the point?