What is this kind of tabular relation diagram called? A relation between two sets can be visualized with a grid-like table in which the rows are labelled along the left with the elements of one set and the columns are labelled along the top with the elements of the other, and in which each cell of the table is occupied by a symbol (usually a dot) if & only if the elements for that row & column are related.  What is this kind of diagram called?
An example:

(I made this image myself, but I'm positive I've seen these charts elsewhere before.)
 A: I would use the term binary heat map - although I'm not sure if there is a unified term. (There are probably other names used in various fields of application.) Heat maps more often display continuous attributes in cells via a color ramp, but there are plenty of matrix like representations of binary data. For instance Bertin in Semiologie talks about reordering the matrix to make certain patterns clearer.
For Bertin's examples (and older ones) see:


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*Wilkinson, L. and Friendly, M. (2009). The history of the cluster heat map. The American Statistician, 63(2):179-184. Online PDF Pre-print
Here is an example figure taken from Wilkinson & Friendly (2009) but is originally from the work of Bertin:

A: I think this is somewhat harder to answer than it would otherwise be because it's a very simple and commonly used style of chart. My answer may not be universally applicable, and other terms are likely to exist for the exact same layout, but I'm finding a lot of similar results in a Google image search for "comparison chart"...so without further references for support (haven't been able to find any yet), I'd recommend calling it a comparison chart. For comparison, another result from my image search:

http://www.utm.utoronto.ca/housing/sites/files/housing/public/users/beamsone/Comparison_chart.jpg

This one is a little more complex, in that it has three kinds of dots (see the legend in the top left corner) and numeric entries on the bottom row. The University of Toronto titles this as a comparison chart.
