Chair Repair

Mario dropped by this evening and took one of the chairs for repair. Seems like he's going to do one at a time. He lives about a 5 min walk from here, so he just picked up the chair and walked back to his place with it. Since 3 of the 4 need help, I guess we just started about a month-long process, if we're lucky.

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Speaking of month-long processes, Feb is now coming to a close. Tomorrow begins the final third of our year in Spain. Time flies.

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Speaking of February, Walla Walla has experienced what is likely the coldest, snowiest Feb on record there. I just keep thinking, glad I missed that!

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I finished reading Everybody Lies by Seth Stephens-Davidowitz. Pretty good. Moving on to Hello World by Hannah Fry. I'll keep you posted.

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Today is a holiday here in Andalucia, but only here in this province. It's called, aptly, Day of Andalucia. It essentially commemorates the founding of Andalucia as an autonomous province of Spain in the year 1980. For us it means no language class, less traffic in town, more pedestrians/tourists on the streets. Lovely weather for it though:

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Packing for a weekend guided trip to Gibraltar and various points in Morocco. Should be fun. Glad Laura's getting a chance to visit the Blue City in Morocco.

Fuzzy Structures

 Tried to prove a conjecture today only to realize that an ortho-convex set might not even be connected. This is something you take for granted with ordinary convexity. I still think my conjecture is true if I add "connected" to my list of assumptions, but you always have to be careful in math. Here's an example of an ortho-convex set that is not connected:

After class, I took a walk towards the fairgrounds that Laura visited yesterday. Along the way, I found this old mosque attractive:

As Laura noted, though the fair isn't until May, the construction on the fairgrounds is well underway. I was struck by this mass of scaffolding that promises to be perhaps the main gate to the grounds when all is completed. It's interesting how, with the scaffolding, the structure almost looks fuzzy:

Expired Registration

About an hour after I went to bed last night, Rachel noted to Laura that the registration on the Honda had expired. Given that the registration is due each June, that would make it really expired. Laura woke me up to let me know. It's weird how you can be 100% sure of something and still be wrong. Well, I was 100% sure I had renewed the registration before we left Walla Walla. I still, even now, seem to have a memory of putting the new sticker on the license plate. However, after searching my records (credit cards, checks etc) in the middle of the night, I was forced to acknowledge that somehow, I didn't renew the registration on the car. So, changing tack, I started figuring out how to renew it. Turns out, it was pretty easy. Just do what I would (and should) have done back in May/June, log on the the registration renewal site and renew the registration. I did that. The registration will go to our house in WW. I gave Halley a heads-up to forward it the Rachel ASAP. And, Rachel will have to cross her fingers that she can make it through another week or so in Miami without getting pulled over by a FL cop for having an expired tag. (Given that she's made it 8 months, there is some reason to hope that she'll make it another week.)

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Speaking of paying things on line for our WW life. The property tax bill came today (electronically). That one I paid right away, even though it's not due until April. That definitely a bill you don't want to miss. I relayed to Rachel after paying the registration that this was only the second time I'd ever missed a payment. The first time was a missed credit card bill the month that Emily was born. I supposed lots of people go through life never missing a bill, but I guess missing two in a span of 30 years or so of paying bills isn't the end of the world.

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In a completely unrelated matter, the chairs in our flat our falling apart:

The joints and cushions all do this to one degree or another. Mario intended to get them repaired way back last summer when I pointed it out to him, but I guess it just slipped his mind (and we didn't really pursue it either). Anyway, we started with 4 of them, but at this point, there's only one left that is really safe to use. I finally sent Mario a message this morning about it. He apologetically said that he'd get right on it. I'd be happy to fix them myself, but I just don't have the right tools.

Math History

I spent most of the day reading about the math history of the idea of "center of gravity". I'm hoping to include a nice overview in the paper I'm writing. Turns out the first recorded mathematical treatment is due to Archimedes in the 3rd century BC. Archimedes of  "give me a long enough lever and a place to stand and I can move the earth" fame. Turns out, that has a lot to do with centers of gravity. Folks in the middle ages sort of rediscovered Archimedes and started applying methods of infinitesimals to the problem of finding centers of gravity of solids. Indeed, their methods were important precursors to the discovery of calculus, particularly the work of Leibniz in the 17th century. It's fun to read about these ideas and at the same time routinely encounter buildings here in Sevilla that predate the development of calculus by some 300 years.

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There were two new students in my Spanish class today. We had a nice time exploring the past tense of verbs like "me gusta". Not sure I could get it right in an extemporaneous conversation, but at least I understand the grammar.

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Didn't walk/run too much today. Still resting a bit of  a foot injury. That said, the two walks I did do today (about a mile each) were essentially pain free. I'm optimistic that I'm past the injury now.

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The winter in Walla Walla won't quit. Normally, this time of year, daffodils are blooming and buds are developing on trees. Instead, it just keeps snowing and giving sub-freezing weather. I'm glad I'm missing it.

Tour de Sevilla

I tweaked my foot, so I'm trying to minimize walk/running on it for a couple of days. Today, to get some exercise, I rode one of the bike shares for about 90 mins. Since you can only keep a bike out of the system for at most 30 mins at a time, I had to stay close to the bike share stations and keep myself on a 25 min timer. I managed to avoid any overages and rode to some parts of the city down south that I hadn't explored before. This part of Sevilla has the other soccer stadium for the other pro team in town, Betis:

The neighborhoods in the vicinity of the stadium are quite nice. Mostly newer construction (within the past 10 to 15 years):

There are several nice green spaces down there too:

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I didn't do much math today. Instead I watched a bit of Netflix and talked to Rachel, Jo-Anne and Kathy on the phone. I tried Emily, but she didn't pick up. I may try her again after I finish up here. I'm hoping to get a start on a draft of a paper this week. Most of the math is done, it remains to write it up in a cohesive and interesting way.