- Why academic writing stinks or, keep it simple (G+)
- Sad news of the death of Ferran Hurtado (G+)
- A visual compendium of glowing creatures, scientific illustration by Eleanor Lutz (G+)
- Women in computer science get tenure at significantly lower rates than men even after normalizing for research productivity (G+)
- Tietze's graph, Wikipedia article expanded with a new illustration of why it has the name it has: it was an earlier counterexample in the theory of coloring graphs on non-orientable surfaces (G+)
- Abdel Kader Haidara awarded Germany's 2014 Africa Prize for rescuing Timbuktu manuscripts (G+)
- Adobe Digital Editions 4 spying on users by sending a listing of the contents of your entire digital library in cleartext (G+)
- NASA Invents a Folding Solar Panel Inspired by Origami (G+)
- Optimal randomized comparison sorting: a question on the CSTheory exchange observing that randomization can break the decision tree lower bound and asking what's known about upper bounds (G+)
- More on the strange scale-free Babylonian concept of number, in which 1 and 60 were apparently indistinguishable (G+)
- Robert le Ricolais’s Tensegrity Models, architectural models that could as well be abstract art (G+)
- European Science Foundation demands retraction of criticism in Nature, threatens legal action (G+)
- SoCG 2015 conference web site and call for papers (G+)

If three sites are given, then these sites determine three pairs of sites, three regions in the Voronoi diagram, and (usually) one or more Voronoi vertices where all three sites meet. Often, these vertices define triangle centers: special points defined from the triangle of the three sites, such that applying a similarity transformation to the plane commutes with constructing the given point. Technically, to get a triangle center out of a 2-site Voronoi diagram, the distance function has to be invariant under congruences of the plane, and if a triangle pqx is scaled by a factor of s then the distance d(p,q;x) has to scale by a factor of s

^{e}for some constant scaling exponent e (possibly zero). But this scaling requirement is true of many natural functions that you might want to use as distances.

By now, thousands of different triangle centers have been studied. Which of them can be generated from 2-site Voronoi diagrams in this way? Here are some examples. (The X(...) numbers are references to Clark Kimberling's Encyclopedia of Triangle Centers.)

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- Algomation animated algorithms (G+)
- Rush hour video, or, what our robot-driven future will be like (G+)
- The Washington Post rants about those evil student pirates, but neglects to mention the free alternatives (G+)
- A song video about knots, from the low-dimensional topology blog (G+)
- Fun hex grid facts, via MF (G+)
- SODA 2015 accepted papers (G+)
- KaTeX, a lobotomized but fast web math renderer (G+)
- Against laptops in lectures, via MF (G+)
- David Wade’s ‘Fantastic Geometry’ – The Works of Wenzel Jamnitzer & Lorenz Stoer on Dataisnature (G+)
- Something about how some data structures I helped develop could improve bitcoin mining (G+)
- 63 and –7/4 are special, numberphile video about prime factors of recurrence sequences (G+)
- Critique of Hirsch’s Citation Index, article in the
*Notices*about how the h-index doesn't provide much more information than the total citation count (G+)

And here's some advice to the students starting the new term, from just outside the conference hall:

^{*}from Würzburg, Germany, where I attended the 22nd International Symposium on Graph Drawing (GD 2014) and was one of the invited speakers at the associated EuroGIGA/CCC Ph.D. school on graph drawing.

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- Unexpected shapes in smoke plumes, as photographed by Thomas Herbrich (G+)
- ISAAC 2014 and COCOA 2014 accepted paper lists (G+)
- FOCS 2014 program and best paper winners (G+)
- Kinetic sculpture made of wooden balls on threads, with some extensive software simulation behind its design (G+)
- How a 19th century math genius taught us the best way to hold a pizza slice, or, a practical application of the theorem that when a flat surface is embedded in 3d, it remains flat in at least one direction (G+)
- Centered octahedral numbers on Wikipedia (G+)
- Interesting esoterica summation (G+)
- A Möbius-Invariant Power Diagram and Its Applications to Soap Bubbles and Planar Lombardi Drawing (journal version of two of my old conference papers; G+)
- Researcher loses job at NSF after government questions her role as 1980s activist (G+)
- Pi visualized as a public urban art mural (G+)
- How not to reference papers (a sad story by Igor Pak of academic misattribution; G+)
- Steinitz Theorems for Simple Orthogonal Polyhedra (journal version of another of my papers; G+)
- Editorial board of
*Journal of K-theory*goes on strike over publisher profiteering (G+)

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There are algorithmic problems that involve this graph and are independent of any representation of it, such as checking whether a first-order logic sentence is true of it (PSPACE-complete). But I'm interested here in problems involving the Rado graph where different ways of constructing and representing the graph lead to different algorithmic behavior. For instance: the Rado graph contains all finite graphs as induced subgraphs. How hard is it to find a given finite graph? Answer: it depends on how the Rado graph is represented.

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- An interview with Haida artist Jim Hart (G+):
- Persi Diaconis discusses mathematics and magic (G+)
- A still-unsolved question about whether it's possible to compute edit distance in sublinear space and polynomial time (G+)
- A New York Times story about how scheduling software makes part-time workers' lives harder. Or does it? The MF discussion of the article makes it clear that managers have been doing the same things with lower tech for a long time. (G+)
- Kerfuffle over SoCG colocation with STOC, later resolved (G+)
- Barrier resilience on Wikipedia (G+)
- Robert Lang talks about the way mathematics done purely for its aesthetic value (in this case mathematical origami) can turn around and have practical applications. (G+)
- The Troll Slayer. New Yorker profile of classics professor Mary Beard, who knows better than most exactly how long men have been silencing women. (G+)
- A study on how social media causes us to self-censor our opinions (G+)
- My UCI colleague Scott Jordan takes a position advising the FCC about net neutrality (G+)
- Sculpture by Zachary Abel, one of my new co-authors on the flat-folding paper (G+)

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*a*,

*b*,

*c*, and

*n*, if

*n*> 2, then

*a*

^{n}+

*b*

^{n}≠

*c*

^{n}. This sentence is fully quantified: the four variables

*a*,

*b*,

*c*, and

*n*are all covered by the quantifier "for all positive integers". It's one of the true ones, if difficult to prove.

But when we're working with the logic of graphs, a (fully-quantified) sentence is itself just another mathematical object, and its truth is relative: it might be true for some graphs and false for others.

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*Her*among them?) but that's not what I'm writing about. Rather, what interests me in this year's contest is the issue of voting systems and their resistance to manipulation.

Some background: this year's award nomination and voting involved a group of fans from one of the subgenres of SF whose two main interests seem to be military jingoism and sexual and racial anti-inclusivity and who have apparently dubbed themselves the "sad puppies". These people pushed a slate of nominees onto the ballot, which then lost fairly decisively in the final voting. There was no unfair vote manipulation going on: everything was aboveboard and according to the rules. But it caused me to wonder: how large would a dedicated faction of the voters have to be to break into the winner's circle, against the will of the remaining voters?

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{7,3,3} Honeycomb, an interesting polyhedral tesselation of hyperbolic space with a fractal boundary (G+)

Some impressive fisheye photography of the heavily patterned interiors of Iranian mosques (G+)

A brief history of mazes and labyrinths, in honor of a new one in place at the Smithsonian (G+)

The journal version of my paper "Grid Minors in Damaged Grids" (G+)

UIUC rescinds the hire of an outspoken critic of Zionism (G+ – as one might guess this led to much discussion)

Stained Glass Windows Made from Stacked Laser-Cut Paper (G+)

(G+)

Hales finally gets computer verification of his sphere-packing proof, with inflammatory statement about journal referees (G+)

Are 90% of academic papers really never cited? For some reason this came up on a Wikipedia deletion discussion: someone wanted to argue that a half-dozen publications with 100+ citations each shouldn't count for much because basically everyone achieved that just by waiting long enough, and used this as evidence. (G+)

Chocolate LEGOs and other edible construction materials (G+)

The museum is mostly devoted to Pacific Northwest First Nations art, but as a living culture rather than as something that happened in the past, so it includes a mix of older cultural artifacts with more modern art. It also has a gallery of Pacific Rim cultures, and a couple of rotating exhibit spaces; for our visit, one of them was on "urban aboriginal youth" and the other was a show of Afro-Cuban art including two sculptures shown above. Definitely worth a visit if you're in the Vancouver area, despite the minor inconvenience of getting there from downtown (we took a city bus).

Obviously, I don't understand the rules of photographic composition. By any rational standard, the tree should not be at the center. It's not the subject, it attracts too much attention to itself there, and centering typically makes the image very static. But when I cropped the shot (mostly to put it into this panoramic aspect ratio) the tree insisted that that's where it had to be. I don't understand why. Also, the small bush on the right, that seems like a distraction, is necessary. I had another version of this image from a slightly different perspective that eliminated the bush, and it didn't work as well. Again, I can't explain why.

Some other Vancouver stuff I enjoyed but didn't photograph: visiting artists' studios, sampling artisinal sake, and learning about summer tree-planting jobs from another sake taster, on Granville Island (do it on a weekday); Shakespeare in the park (The Tempest, but they're also showing Midsummer Night's Dream if you haven't already seen that one more times than you can count); sushi at Miku (across the street from my hotel) and bubble tea next door (we have plenty of that at home but this one had even more variety); Douglas Coupland's big art show at the Vancouver Art Gallery (apparently he's not just a famous author); and waffles and berries for breakfast (there are several cafes that specialize in this — the one we chose was on Pender between Nicola and Broughton).