November 16, 2014

6:03 AM | Linkage
An experiment in allowing journal reviewers to reveal their names (the G+ post has several additional links on academics including some well known graph theorists taking money to deliberately distort university rankings)Pumpkin geometry: stereographic projection of shadows from carved balls (G+; no actual pumpkins involved)Clint Fulkerson: an abstract artist whose work feels somehow both geometric and organic (G+)Paper popups by Peter Dahmen (G+)Crochet Platonic polyhedra by June Gilbank […]

November 09, 2014

9:12 AM | The length of a 2048 game
Presumably many readers have seen and played the 2048 game, in which one slides tiles in different directions across a grid, causing certain pairs of tiles to combine with each other when their sum is correct (in this case, when the sum is a power of two):Or if you get bored with it there are many other variations, some of which have different combining rules, for instance there's one where tiles only combine when their sum is a Fibonacci number. I have the impression this all started with […]

November 03, 2014

6:39 PM | Omelas privacy
A recently posted critique of a critique of differential privacy reminded me of this example, which I've named after of Ursula LeGuin's thought experiment The Ones Who Walk Away from Omelas. (If you haven't read that, you should. And it probably doesn't help to know that Omelas is "Salem, O." spelled backwards.)Suppose that we have a society that values the privacy of its citizens' medical records, but yet wants to publish data that will enable epidemiologists and other researchers to find out […]

November 01, 2014

5:47 PM | Linkage for (the day after) Halloween
Kinetic origami sculpture by Jo Nakashima (G+)How pineapples help finding Steiner trees (G+)ICALP 2015 conference web site and call for papers (deadline Feb.17; G+)Mass resignation from an open access journal (G+)A hardness result for organizing your Google Scholar profile (G+)Wikipedia, a Professor's Best Friend, and a tangential note about binary logarithms (G+)When women stopped coding, an analysis of why and how long we've been seeing a decline in the number of women in computer science […]

October 26, 2014

11:21 PM | Another 5-permutohedron
I've been playing with the Cayley graphs of the symmetric group again, after accidentally running across the Wikipedia article on the icositruncated dodecadodecahedron and thinking "oh yeah, that's the polyhedron that geometrically represents the Cayley graph generated by a transposition and a 4-cycle".Only, it's not. That was a different star polyhedron. So is the icositruncated dodecadodecahedron also a permutohedron? And if so, what are the generators of the corresponding Cayley graph?To […]
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