barcelona, one week later (updated; also, post #600 ..!)

there are no afternoon lectures at the summer school today. they've set aside the time for a cultural excursion to la sagrada familia, an unfinished work of gaudí.

admittedly, i'm tempted to renege on my promise, stay in the dormitory, and instead, work on the draft of a long-promised research paper. lately i've felt like i've had no time to be productive.

then again, i remember what happened last weekend.

maybe it's time to visit the city center of barcelona.

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epilogue: it was worth the trip. i learned and relearned the following facts:

1. never count on groups of mathematicians arriving on time.
   
   a colleague and fellow train companion was worried that we would miss the second tour group, at 17:10. when i pointed to all the other summer school participants, equally late, on the same train car, she was not wholly convinced.
   
   it wasn't until reaching the site that we promptly joined the first tour group, which was 20 minutes late.
   
   
2. an (empirical) symmetry principle. [web photo]
   
   from wikipedia: The Catalan architect Antoni Gaudí made extensive use of catenary shapes in most of his work. In order to find the best curvature for the arches and ribs that he desired to use in the crypt of the Church of Colònia Güell, Gaudí constructed inverted scale models made of numerous threads under tension to represent stones under compression. This technique worked well to solve angled columns, arches, and single-curvature vaults, but could not be used to solve the more complex, double-curvature vaults that he intended to use in the nave of the church of the Sagrada Familia. The idea that Gaudi used thread models to solve the nave of the Sagrada Familia is a common misconception, although it could have been used in the solution of the bell towers.
   

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in other news, this is my 600th post on this blog. (yes: i've been complaining about mathematics and academia for that long.)