Projector

Continuing to get to know my centroid problem. Worked a couple of interesting and confirming examples this morning.

I tried to use the pen on my Dell tablet today, but the batteries were dead. This pen takes 1 AAAA battery and 2 319 batteries. Neither of them seem to be available in the stores around here, so I ordered them on Amazon.es. The pen on my surface still works, so I'll just stick with that for now. It does suggest that the pen issues I had with my Dell earlier may have simply been low batteries. We'll see.

I did a little extra Spanish today since it's a class day. We had 3 students today (including me), so much more like a normal class. I like this teacher, she's not afraid to correct you. The teacher I had last semester was much more lenient. I think I learn better when somebody is correcting me in real time.

I went to the grocery story today for the first time since getting back to Spain. Laura had prepared a lot of meals over the weekend before I got here, so we were pretty well stocked for a bit. Now it's back to the more normal pattern of shopping every day.

It was rainy this afternoon. Here's an uncharacteristically gloomy picture of the river:

After dinner, I decided to have one of my Christmas beers--a Blue Moon. A nice change of pace from the usual Cruzcampo:

There's an interesting advertising campaign down at the river. Projectors are shining across the river to paint these movie posters on the Triana bank:

The images are remarkably clear for a projection across maybe 200 meters. My shadow was razor sharp:

I read another chapter of Factfulness. The lesson of the evening is to not assume that data can be projected forward linearly. If that were the case, your cute children that grew so quickly in their first years would be 20 feet tall when they graduated from high school. He goes on to note that the world population growth has already leveled off and that the actual population will level off by about 2100 at about 11 billion. After that, it's likely to begin to drop.

Coercive continuous functions

Did you know that a coercive, continuous function on a closed set has a global minimum? Neither did I until today. It's a good theorem. Just what I needed.

I made a list and mostly stuck to it today. Productive day.

Here's my Spanish verb spreadsheet. Definitely good practice. It's slow going right now, but my hope is to develop a bit of an instinct for conjugation:

I continued reading Factfulness today. The lesson for today is that people tend to be biased towards pessimism when it comes to human progress. Though the data supporting an improving world over the past two centuries is overwhelming, we nevertheless think that the world is getting worse. Rosling attributes this to a natural tendency to pay attention to negative things and to ignore positive things because negative things are threats to our existence and positive things aren't. From an evolutionary perspective, we are selected to pay attention to negative things because that improves our chances of survival. As such, we consume media that is predominantly bad news, choose politicians that campaign on fear, and talk to each other mostly about negative things. We're not built to see the positive things--especially on timescales of centuries, but the data is undeniable.

I walked another 5 miles today. I'm putting off running for another couple of days. I need to ease back into it. It's amazing how many electric scooters there are in Sevilla:

Piety

I slept until 9:30am this morning--very late for me. Still jet lagging I guess. In an effort to get back into the groove, I made a schedule of activities today and mostly stuck to it. Largely because of that, I was pretty productive today.

I read a couple of interesting articles about centroids (centers of gravity). The notion dates back to Euclid and Archimedes, but no one really knows where it originated. It's such a basic idea that it probably didn't originate with a single mathematician, but rather just emerged. The centroid is the balance point of a shape. For example, if you've ever balanced a plate on one finger, you found the centroid of the plate. The problem of finding such balance points is a recurring theme in geometry. I've been interested in developing a generalization of the centroid. This new project has me reading as many papers about them as I can.

My next task was to review my Spanish. I started my next Spanish language class today. Having been thinking and communicating in English for the past two weeks, my Spanish is rusty. I made some good progress there. I found a spreadsheet containing over 600 Spanish verbs and their conjugations in 20 different tenses. Laura helped me to cut out a lot of the tenses that I don't need right now and to focus on just 5 of them. Now I can pick a random line in the spreadsheet and practice conjugating.

I've been trying to read books that might be valuable to the data science class I'm developing. I finished Homo Deus by Yuval Noah Harari. A deeply philosophical, but clarifying look at human history. The burning unanswered question of the text ends up being: What is the purpose of our conscious awareness? Without a clear answer, the inevitable course of human development seems to be usurpation by unconscious artificial intelligence. I've now moved on to Factfulness by Hans Rosling (thanks Rachel). The premise of this book is that we seem to have an unwarranted negative view of the state of our world. We think that most of the world is poorer, more violent, and less educated than it actually is.

My new Spanish class was good. My new teacher, Piedad (means 'piety' in English), is very nice. Sadly, I was the only one of the 4 students enrolled in the class to show up today. I think this is largely the result of an email from the school administration saying that the class wasn't going to meet on Mondays moving forward. I checked in with the school this morning and was told that the class was returning to its original Mon/Wed schedule. I suspect that the other students in the class were not told of this return to normal. That said, it was nice to have 90 mins one-on-one with the teacher.

I didn't do my river walk until after class today. It was cool as the sun dipped, but the sky was lovely:

This sad sight is the end of the milk duds I brought back from the US. Jo-Anne bought a couple boxes for me before I left. They're not available here in Spain and Laura and I really like them every once in a while:

Eh, this is far enough

The flights to Lisbon and then Sevilla went smoothly. I didn't sleep much, so I'm looking forward to bed tonight. The only real hitch in travel was the airport bus downtown. The bus stopped about 2km from the flat and the driver walked through and kicked everybody off and drove away. Being an airport bus, there were a lot of flummoxed tourists standing on the side of the road in the middle of Sevilla. I was glad I'd lived in Sevilla for 7 months or I'd have been flummoxed right along with them. Turns out there was a half-marathon going on and the bus route was blocked. I just hitched up my drawers and walked the rest of the way home. The only real challenge was the race route kept getting in my way in places where I needed to cross. I just waited patiently and scooted across between runners with my roller bag. Nearer to home, the runners were pretty spread out and crossing was easy:

I made it to the flat and even found my keys which had been beating around my backpack for the past two weeks. I let myself in and hugged Laura for a while. I sat around a bit out of sorts and tired. Eventually I laid down and napped for 2 hours.

After my nap, just to get my blood moving, Laura and I went out for a short walk in the cool, clear evening. It was nice to get reacquainted with the city. The light was lovely for photos, so here are a few:

Back at the flat I checked in with Keith for a bit. He's a bit isolated now back in Rehoboth Beach with the rest of us all departing yesterday at the same time. I also called Rachel and eventually added Emily to the call. After about a half hour, I deftly handed my phone off to Laura who continued the conversation.

This evening, Laura and I resumed watching The Marvelous Mrs. Maisel on Amazon. Great show. We only have one episode left.

Tomorrow, back to math, exercise, Spanish etc as life settles back down to normal.

Back to Sevilla

We did some last-minute clean up and packing of my mom's house while a couple of home inspectors looked it over to let us know of any serious issues in the home. Kathy packed up her car with a bunch of photos. Jo-Anne with other keepsakes and documents. Keith came over and took Jake and the cat over to his house. We also learned that the two dogs, Donnie and Midnight, will be adopted by Shine's sister, so they'll go from being siblings in one house, to cousins in two houses.

While we were working, a FedEx truck drove up and dropped off two donuts from The Salty Donut sent by Rachel from Miami. The Salty Donut is her favorite donut shop. On the left, we see the STICKY BUN DONUT Knaus Berry Farm sticky bun wrapped inside our 24-hour brioche dough, brushed with secret sauce, wrapped and topped with homemade pecan toffee sauce. On the right, SEA SALT CREAM + COOKIES 24 hr. brioche filled with a homemade edible cookie dough cream, ‘melted ice cream’ glaze & topped with chunks of homemade chocolate chip cookie & maldon sea salt:

They were both very good.

Here's Jake enjoying his last moments on his favorite love seat before being carted off to my brother's house:

 Here's a photo of my mom's 4 children just before we all went our separate ways:

From left to right, me off to Sevilla, Jo-Anne back to Michigan, Kathy to Virginia, and Keith who lives in Rehoboth Beach.

I drove a rental car up to Newark Airport. The drive was uneventful and I left myself enough time to not be stressed as I navigated the rental car return and customs. You can see downtown NYC from some of the gates in the airport. If you look just above the wing here, you can see the NYC skyline off in the distance:

My flight is pretty efficient. 6 hrs to Lisbon, an hour to Sevilla. About 9 hrs gate-to-gate.