Thursday, February 28, 2019

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.


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


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!


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


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:


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.

Wednesday, February 27, 2019

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:

Tuesday, February 26, 2019

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.)


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.


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.

Monday, February 25, 2019

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.


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.


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.


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.

Sunday, February 24, 2019

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:


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.

Saturday, February 23, 2019

Guided Tour

Palma and Mario came over this afternoon around 5pm and took us on a walking tour of the city. They spoke alternately in Spanish and English. During the Spanish I guess I was getting about 50%. Palma told us about several churches in the Alameda neighborhood. I think she know the area well because she used to live there. We also walked in front of the school where Mario teaches. Built in the 60s, it has the feel of a Soviet style concrete building. Even the tiled murals are things we could easily have seen in Budapest:

Along one of the streets during the walk, we encountered some men practicing for the processions of Semana Santa (in April). I guess it only occurred to me today that carrying a 2000lb paseo is a physical activity that you must train for. These guys were carrying a platform stacked with steel I-beams and they were working:

Here's a close up of them walking by:

 The weather was warm this evening. Palma says that we've enjoyed an unusually mild winter here:

We stopped for tea in a cafe on the way home. We discussed politics. It's interesting how the rightward turn of Spanish politics is just as concerning for many Spaniards as our own baffling rightward turn in the US is to us. They asked us about Trump and whatever the latest horseshit emerging from that corner is. I got the sense that they were trying to get tips on how to process the emerging idiocy in their county by asking people that are dealing with already. Sadly, I don't think we were much help, haha.


I found a few good references for some math I'm working on today. Scott read over my proof from yesterday and seems good with it.


I have a bit of a pain in my right foot, so I'm taking it easy on the running for a couple of days.

Friday, February 22, 2019

Green Book

I got up early this morning and noticed the moonlight reflecting off of the tile floor in the living room:


Had a good math day today. I finished the draft of a proof of a result. It seems solid, but it'll have to sit for a few days before I'm sure. I've been collaborating with a friend from graduate school, Scott Dillery, on this recent effort. We'll see if he can poke some holes in it.


Laura and I went to see the movie Green Book at the one theater here that screens movies in English. Great film, highly recommend.

Thursday, February 21, 2019

Pitcher Picture

Pretty ordinary day today, though good. Made some progress on a proof. I think I see my way to the end of it by tomorrow. Continued my current DataCamp class on decisions trees. Did a run along the river (lovely weather). Did a load of laundry (good laundry weather). Bought a second pitcher for iced tea:

Iced tea is my staple drink at home. It's nice to have one "on deck" when the current pitcher runs out. Of course, I won't be able to start that new strategy quite yet because I'm out of tea bags (they're on the shopping list for tomorrow).

Hope to finish the proof tomorrow and start thinking about what the paper will look like.

Wednesday, February 20, 2019


I guess exterminators are part of everyday life in most cities. Today we noticed one parked in front of our building today apparently working in some spaces in the building across the street. I magnified part of the truck so you can see the words "Control y Tratamiento de Plagas":

I like the word "plaga". It sounds biblical, though in Spanish its more like "pests".

Of course, when you run a restaurant, like the guy in the green circle, having an exterminator parked in front of your restaurant is not really ideal for attracting customers. Round about lunch time, when green circle guy wants to open up the restaurant, he starts following around the exterminator guys I guess trying to get them to wrap it up. To be fair, the truck was parked in the area where he sets up outdoor seating, so I'm sure that was part of it.


On a more humorous note, later we heard a gaggle of kids in front of the building. Looking out, we saw this:

Now that's a plaga. Better call the exterminators...


It's good being married to a mathematician. I shared some work with Laura today because I was getting results that seemed counterintuitive to me. Laura came up with a very intuitive explanation for what I was seeing that led to some real insights. A lot of math progress today.


I learned that the other longest attending student in my Spanish class, Jake, was a child actor for a BBC children's show called the Green Balloon Club. It ran for several years and nearly 40 episodes. He really enjoyed doing it. They made one episode a month over an intense 3 day period. You can see it on youtube. His name is Jake Pratt.

Tuesday, February 19, 2019

Interior Spaces

The relatively ordered streets of Sevilla hide a ridiculously complicated interior. Every time I go up on the roof to hang laundry, I look around at the interior spaces below and am astonished at the maze of confusion:

On the other hand, lots of folks seem to have their own private rooftop sanctuaries complete with chairs and astroturf. I kind of wish we had that. It would be nice to have a private place to sit outside. In our building, it's against the rules to just hang out on the roof. You're only allowed to use it for laundry.

It was a partly cloudy day today, but pleasant. The sunset was nice from the roof as I took down the laundry:


I did a lot of math and managed to task switch to a DataCamp course on Decision Trees. I also started reading about the history of "center of gravity" and "centroid" for a paper I'm starting to write. These ideas are so old and so basic that you can't attribute them to a single individual. As long as there have been engineers and builders, there have been people figuring out the center of gravity of shapes. That said, there's a lot of interesting math history about who did what with centers of gravity. Even Leonardo Da Vinci is said to have computed the center of mass of a tetrahedron and a pyramid of any number of sides.

Monday, February 18, 2019

Mallorca → Sevilla

The sunset yesterday evening was lovely:

There were a few people along the shore to watch and a busker playing some songs on a guitar (quite good). It wasn't the raucous event  of a Key West sunset, but beautiful nonetheless.

After dinner, we watched a classic lounge singer in the hotel bar for an hour. The standard stuff, Sinatra, Diamond etc, plus a few Spanish tunes thrown in for authenticity. His banter was mostly in German even though he was a Spaniard. This is because Mallorca appears to have more German tourists than any other nationality by far. There are German restaurants and bars, beer and pretzels and the staff all spoke at least German and English in addition to their native Spanish.


This morning we woke to heavy fog:

So different from the sunset the night before. We grabbed breakfast at the hotel, checked out, and headed down to the bus stop to catch the 8am bus to the airport. The trip back was uneventful. We reached Sevilla on time, caught bus back into town, and were in our flat around 12:15pm. All in all, a good trip.

We both practiced a bit of Spanish before heading to our respective classes at 4pm. After class, I did a fast 5 mile walk along the river. I did a little math, took a shower, had dinner and put on my PJs. Ready for bed now.

Sunday, February 17, 2019

Sevilla → Mallorca → Mallorca → Menorca → Mallorca

Laura and I decided to spend the weekend in Palma, a Spanish city on the island of Mallorca in the Mediterranean. It's only about a 75 min direct flight from Sevilla, so we thought it would be a snap, haha. We had an early flight out of Sevilla so we got up around 4am, hiked to the bus stop and caught the bus out to the airport. We got there pretty early and hung out at the gate. Our flight (Vueling Airlines) left on time and we headed towards Mallorca. Though it was sunny, there was a persistent fog bank at the airport. The pilot warned us that it could be a problem. We tucked in for landing. With the wheels of the plane feet above the runway, the pilot gunned the engines and we flew back up into the sky steeply. We did a long, 15 minute loop back around for another approach. Once again, with wheels just above the tarmac, the pilot gunned the engines and we flew off. Shortly after this aborted second landing attempt, the pilot informed us that we were diverting to Menorca--a small island about a 15 min flight north and east of Mallorca.

It's not really clear to me what the decision-making process is for getting a plane within feet of landing and then deciding to abort (twice). Isn't there someone on the ground that can advise the pilot so that such a dangerous maneuver isn't necessary?

We landed in Menorca without incident. We sat on the plane for about a half hour, presumably waiting for the airport in Mallorca to clear. After a while, they booted us off the plane (so it could be used elsewhere) and we all wandered into the Menorca airport.

The most frustrating part of this whole thing wasn't the fog, weather happens. It was the utter lack of communication and guidance for the abandoned passengers once we deplaned in Menorca. Also, the little communication that did occur happened in Spanish. OK for us, we kind of got it, but there were a large number of folks on the plane that didn't speak Spanish.

Luckily, I had Laura. She alertly identified the right people, listened in on conversations of other passengers, and talked to folks at the ticket counter. Eventually, she found the correct line and got us re-booked on an Iberia flight at 3:15pm. She also got us some food vouchers for the airport restaurants. We killed a few hours in one of the restaurants (which, pleasantly, had some good lunch dishes), and left for our 25 min flight to Mallorca--getting there a mere 7 hours later than planned.

Just to get some exercise, we decided to walk from the airport to the hotel. It was about 4 miles. There were a few pedestrian unfriendly stretches near the airport, but once we got down to the beach area, it was a nice walk. At one point, we walked along a dirt road with some very old looking stone dwellings:

We made it to our room and enjoyed a nice meal at the hotel:


This morning we walked farther along the beach to some cliffs. We passed along some lovely shoreline properties. I particularly enjoyed the "Beware of Dog" tile on this entryway (it's worth zooming in on, I wouldn't want to be anywhere near that dog):

The cliffs were lovely:

The water was very blue and clear. We saw lots of sailboarders and even a snorkeler out there:

Back on land, cycling is a massively popular activity. This sign showed popular bike routes all over the island (it's about 150km across at some points):

There have been a number of stages of the Vuelta a Espana here in Mallorca.

We leave tomorrow.

Friday, February 15, 2019

Task Switching, F

I failed task switching again today. I was checking some math I did last week by applying it to some examples. Things were not working out. So I redid most of the work looking for my mistake. I also emailed a collaborator on the work with a warning that some notes I'd written up and shared last week were wrong. He got back to me and in his response, I figured out what I was doing wrong. I'm about halfway through fixing the issue, but it took most of the day and I was unable to task switch away from it. Oh well.


Another lovely day in Sevilla. I've been meaning to photograph these flowers down by the river for a while now:

They look a bit like poppies, but they're not.


I read an interesting article in the New York Times about the dwindling middle class in Spain. The economy is ok, but the jobs aren't very high paying and there's increasing wealth inequality. The barely left-leaning national gov't fell apart today and there will be elections in April. The recent success of the right-wing Vox party here in Andalucia's local elections has folks nervous there there could be some right-wing nationalists elected in April to national positions. I don't see any reason why Spain should be immune to right-wing whack jobs since none of the rest of us (US, France, England, Germany etc) are. We'll just have to wait and see.

Thursday, February 14, 2019

Pineapple right-side up cake

Happy Valentine's Day! Laura made me (and her class) a pineapple upside down cake. Lacking a non-stick spring form cake pan however, forced them to be right-side up cakes. They were still mighty tasty:


The water works guys must've worked through the night because our water didn't return until this morning.


I made some progress on a data science project I've been working on recently. I was a failure at task-switching though. I basically worked on the same thing all day. Tomorrow I'll do better.


I did manage to switch over to reading Everybody Lies this evening. He described the proliferation of A/B testing on-line. Websites randomly offer visitors small variations in wording, icons, arrangement etc. They keep track of what people prefer and use those preferences to determine the final form.

I also learned about the myth of elite schools. For example, students that got into both Harvard and Penn State, but chose different schools had the same outcomes in terms of later earnings. Even though Harvard is perceived as more prestigious, it does not change outcomes for similar students.

Wednesday, February 13, 2019

No hay agua

We got a notice in the mail last week that there would be water system testing and disruptions to service over this week. The notice claimed that there only be shutoffs in the wee hours. Clearly something went wrong today:

Those are the dirty dishes in our sink from lunch today because there's no water to wash them with. Somehow the bar across the street did lunch today, but the owner walked down the street to "talk" to the workers quite frequently:

The water was still off when we went to our respective language classes at 3:30pm. It was still off when I got home at 6pm. I went out for a walk along the river and took this picture:

 It was still off when I got back at 7:30pm. I met Laura at a nearby bus stop at 8pm and we went to Ikea in Tomares to get me a lap desk:

The poor guys were still working in the street when we passed by at 9:30pm. However, when got into our flat, the water was at full pressure.


My lap desk is nice. I'm using it as I write this.


We made some last-minute plans to go to Mallorca this weekend. Mallorca is an island part of Spain in the Mediterranean.

Should be interesting. Our flight leaves early Saturday and returns Monday around midday.

Tuesday, February 12, 2019

It's Not Dead

I've been seeing this cat on my walks/runs along the river lately. Today it was stretched out on the path:

As busy as this path is at this time of day, the cat demonstrated remarkable equanimity. I don't think it was dead, haha.

After dinner this evening, I took the trash out and decided to keep going. I walked over to the cathedral area. Not many people around this time of year even though the weather has been wonderful:

This is the first time I've seen the Giralda since they removed the renovation scaffolding on this face:

You can definitely see the improved surface.

On the way home, I passed through Plaza Nueva. There are three bike stations there, just like this one:

Every morning the one near our house is empty, but these stations seem to always have hundreds (or at least dozens).


I continued reading Everybody Lies today. I read about an interesting study of successful people (defined as having a Wikipedia page about them). Turns out they're much more likely to come from diverse, urban areas than homogeneous rural areas. A study on upward mobility shows similar patterns. There are places in the country that have fantastic records of upward mobility and other places that are like caste systems where there is virtually no upward mobility. As the author points out, big data doesn't just identify where things are going wrong, but where things might be going right.

Monday, February 11, 2019

Wiggle, wiggle.

I had a productive morning of mathematics. I also had a nice Spanish class this afternoon. One of my classmates, Jake, is from the UK. He's probably around 23 years old. He's come to Sevilla for a few months on his own dime. He's basically a street dancer and supplements his income by busking around the cathedral on weekends. He shared that this weekend the police were particularly aggressive about clearing out buskers. He was chased out of a number of locations that he'd used before. To his credit, he has looked into getting a permit. However, in classic Spanish bureaucracy, while there does appear to be a busking permit on the books, no one knows where you can apply for or get one. Even the police have no idea, as Jake claimed was discussed in one of his encounters this weekend.


I continued to read Everybody Lies. An interesting revelation about large internet companies like facebook and google, even when the entire country seems to be up in arms about some issue or other, behind the scenes on facebook and google, data scientists know that often times the outrage is disproportionate. I.e. that there exists a greater number of people that are quiet supporters of the issue or simply ambivalent.


I went for a bit of a walk after class today. I still admire the scope and variety of graffiti here. This wall looked particularly striking in the dusk:

Our bridge in the calm dusk:

I've only recently noticed this plaque commemorating the famous Camino de Santiago on the east end of our bridge:

I didn't realize that there were segments of the route here in Sevilla, or even in Andalucia. I thought the majority of the route was in northern Spain. If you look at the map here:

you can see that the primary route is in northern Spain, but that there are a number of "tributary" routes including the one that terminates in Sevilla called "via de la plata". I guess this marker is a waypoint on that trail.

Finally, there's an old English sheepdog in our neighborhood. I saw him out for his walk this evening along the river. I like they his fluffy butt wiggles when he walks:

Sunday, February 10, 2019

Pizza Day

Laura made pizza for lunch and pizza for dinner. For lunch, she employed a technique we've used before here in Sevilla--she used pitas as crusts for "personal" sized pizzas. I've always liked them, but she is less than thrilled with the pitas-as-crust recipe. This afternoon, she found some yeast and made a pizza dough of her own. We had that for dinner:

I managed to snap a picture before it was gone. I liked this one too. Plus, you can't have too much pizza.


Other than pizza, it was a pretty low-key day. Did some laundry, some math, continued reading Everybody Lies, talked to Rachel briefly, and watched a bit of Netflix.