Gave an introduction to hierarchical cluster analysis, dendrograms, and barcodes. Illustrated these notions through two examples: 1) clustered five objects for which pairwise distances were given; 2) counted the number of objects in the following digital photo, and counted the number of these objects that have holes in them.<br>
<center><img src="uploads/image132.png" width=5height=5></center>
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During the lecture I illustrated dendrroagrams and barcodes using the <a href="https://www.gap-system.org/">GAP</a> software system for computational algebra. The code for reproducing the examples is <a href="uploads/L8.txt">here</a>.