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Dirk Lorenz

@dirque.bsky.social
1.1K followers 358 following 565 posts

Doing mathematics, also as a job. Now at Uni Bremen, was at TU Braunschweig. Only here for the math. Optimization, inverse problems, imaging, learning - stuff like that.

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Dirk Lorenz @dirque.bsky.social · 08/06/2026
I remember playing Civ 1 with somebody and we needed quite some time to figure out that Russian and Chinese looked exactly the same to him...
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Dirk Lorenz @dirque.bsky.social · 02/06/2026
That's a hell of a venue for a plenary talk here at #SIAMOP26
Photo of a very fancy old lecture hall from University of Edinburgh
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Dirk Lorenz @dirque.bsky.social · 16/03/2026
Modern technology makes conference evenings in the hotel much more enjoyable!
An electric guitar with a headphone amp in a hotel chair
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Dirk Lorenz @dirque.bsky.social · 23/01/2026
The potato meme: A picture of a baked potato with the text "Let the potato rest for five minutes"
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Dirk Lorenz @dirque.bsky.social · 19/01/2026
Universidad Técnica Federico Santa María in Valparaiso has a quite iconic campus tbh
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Dirk Lorenz @dirque.bsky.social · 31/12/2025
These tiles don't cease to amaze - with hexagonal holes you get a lot of symmetry!
Another periodic pattern with holes made of aperiodic tiles
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Dirk Lorenz @dirque.bsky.social · 28/12/2025
And they mix! 🧮 #mathsky
A periodic pattern with hexagonal holes made out of the einstein monotiles
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Dirk Lorenz @dirque.bsky.social · 28/12/2025
And another one!
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Dirk Lorenz @dirque.bsky.social · 27/12/2025
New periodic pattern from aperiodic tiles dropped: 🧮 #mathsky
A periodic pattern out of Einstein monotiles (with hexagonal holes)
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Dirk Lorenz @dirque.bsky.social · 19/06/2025
I sample points uniformly on the sphere and then look at them on a map (in longitude and z-coordinate). STILL UNIFORMLY DISTRIBUTED! 🤯 (Quite a nice fact that is special to three dimensions: Each coordinate of a random vector uniformly on the uni sphere is uniform in [-1,1].) #🧮
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Dirk Lorenz @dirque.bsky.social · 02/06/2025
Look at what I produced! (\usepackage[cm]{sfmath} for more drama).
LaTeX output of \bar{\underline{\Xi}} with \usepackage[cm]{sfmath}
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Dirk Lorenz @dirque.bsky.social · 27/04/2025
Very nice! Reminds of this poem by the Austrian writer Ernst Jandl
Text of Ernst Jandl's Poem "glückwunsch"
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Dirk Lorenz @dirque.bsky.social · 04/04/2025
Well, there is this (taken from www.lesswrong.com/posts/Ng5n8F...), so is likely in the 75%-95% range…
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Dirk Lorenz @dirque.bsky.social · 19/03/2025
A mobile with cloth pins for some photos (and other light stuff). Sculptures of a thinker and of Ganesha (both presents of former group members).
Picture of my office mobilePicture of the thinker and Ganesha
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Dirk Lorenz @dirque.bsky.social · 17/01/2025
Another graduate student! Second to last one from TU Braunschweig - Emanuele Naldi graduated today with distinction! (Off topic remarkv Tbh, the best fitting suits I've seen in a thesis defense.)
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Dirk Lorenz @dirque.bsky.social · 14/01/2025
@tomkalei.bsky.social finishing his talk in our Colloquium on "The theories of oids" 😉
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Dirk Lorenz @dirque.bsky.social · 13/01/2025
Can be found quite frequently on menus in Italy. It's called Pizza Americana and some Italian twentysomethings told me that this was their favorite childhood option.
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Dirk Lorenz @dirque.bsky.social · 10/01/2025
Nice to be back to my old view! And it comes with some snow!
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Dirk Lorenz @dirque.bsky.social · 06/01/2025
It's a good idea indeed. It is so good that many kids in Germany between age 3 and 6 have this as one of their main modes of transportation. They still may need a few days to transition to a paddling bike though.
A kid on a "Laufrad"
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Dirk Lorenz @dirque.bsky.social · 04/01/2025
How about this? Looks like a line integral (along a non-closed line) to me btw
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Dirk Lorenz @dirque.bsky.social · 02/01/2025
I am at the point in my life where the family calendar gets smaller
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Dirk Lorenz @dirque.bsky.social · 16/12/2024
Our awesome students made this announcement of the Christmas lecture I am about to give tomorrow here @unibremen.bsky.social !
Hand painter poster of the announcementTitle picture of presents under a Christmas tree and the title "How to get your presents (fast)"
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Dirk Lorenz @dirque.bsky.social · 13/12/2024
I have an open postdoc (or phd) position! You know PINNs? You are interested in hands-on applications and love to work in a larger project? Then this position is for you! Please reach out if you have any questions! (Job ad only in German, unfortunately…) www.uni-bremen.de/en/universit...
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Dirk Lorenz @dirque.bsky.social · 10/12/2024
Email is a trap
xkcd comic from https://imgs.xkcd.com/comics/inbox.png
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Dirk Lorenz @dirque.bsky.social · 09/12/2024
Ok
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Dirk Lorenz @dirque.bsky.social · 07/12/2024
Post someone you've been told you look like who you definitely don't look like.
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Dirk Lorenz @dirque.bsky.social · 06/12/2024
People discussing who was first to use attention while clearly it was Fermat who introduced the concept of attention to scientific research with his marvellous margin note.
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Dirk Lorenz @dirque.bsky.social · 02/12/2024
Boooring
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Dirk Lorenz @dirque.bsky.social · 20/11/2024
Something like this?
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Dirk Lorenz @dirque.bsky.social · 19/11/2024
A meme from the Simpson where Homer (standing for Kyle) says to Bart (me) "You are not a sailor *yet*"
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Dirk Lorenz @dirque.bsky.social · 18/11/2024
Google scholar turned 20 and this is how it's celebrated
A screenshot of the "Google Scholar Doodle"
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Dirk Lorenz @dirque.bsky.social · 15/11/2024
Posting some stuff I made some time ago. #mathsky
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Dirk Lorenz @dirque.bsky.social · 20/09/2024
Bluesky now has over 10 million users, and I was #794,815! Funny enough, that I joined on my birthday
A virtual certificate with text "Celebrating 10M users on Bluesky, #794,815, Dirk Lorenz ‪@dirque.bsky.social‬, joined on Aug 30, 2023"
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Dirk Lorenz @dirque.bsky.social · 06/08/2024
Well, I for one do not care for the Japanese chalk. Here in Germany we have awesome blackboards. No need for fancy chalk. Hagoromo does not write any better than the quite cheap Giotto Robercolor
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Dirk Lorenz @dirque.bsky.social · 06/08/2024
www.usatoday.com/story/sports...
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Dirk Lorenz @dirque.bsky.social · 06/06/2024
I seriously consider leaving the club if this fails again. As someone once said: I don't want to belong to any club that will accept me as a member.
Picture of Groucho Marx and the quote "I don't want to belong to any club that will accept me as a member."
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Dirk Lorenz @dirque.bsky.social · 30/05/2024
Sad news: Hans-Friedrich Münzner passed away recently on May 25, 2024 shortly after his 86th birthday. He is the guy who taught my analysis 27 years ago. His first words in Analysis 1 were "Numbers serve two things: Counting and ordering things" and somehow this got me hooked.
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Dirk Lorenz @dirque.bsky.social · 03/03/2024
Simple, yet effective!
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Dirk Lorenz @dirque.bsky.social · 03/03/2024
Quite proud that I could work out the proof myself! 3/n, (n only 3)
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Dirk Lorenz @dirque.bsky.social · 22/01/2024
Still fascinated by the output of plt.plot(np.sin(np.arange(2000)),linestyle='',marker='.') 🧮 #mathsky
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Dirk Lorenz @dirque.bsky.social · 06/01/2024
Wolfram alpha lets you choose the normalization of the Fourier transform in a drop-down menu! Very neat!
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Dirk Lorenz @dirque.bsky.social · 26/12/2023
I got level sets of bears for Christmas! 🧮
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Dirk Lorenz @dirque.bsky.social · 19/12/2023
🧮 #mathmeme
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Dirk Lorenz @dirque.bsky.social · 29/11/2023
Seems like the app formerly known as Twitter is broken...
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Dirk Lorenz @dirque.bsky.social · 27/11/2023
I can't recall a time at which I found such an illustration in a math book helpful. (It's from Luenberger's "Optimization by vector space methods" which is awsome. But this illustration… 🙄
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Dirk Lorenz @dirque.bsky.social · 27/11/2023
Despite the delay I made it from Gare du Nord to Gare de Lyon on time and could by last leg. TGV to Lyon!
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Dirk Lorenz @dirque.bsky.social · 27/11/2023
German and French trains working together neatly: My delay on my way to Cologne is nicely captured by a delay of the train to Paris 😂
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Dirk Lorenz @dirque.bsky.social · 27/11/2023
Off to a half-day long train ride to the DIPOpt workshop on deep learning inverse problems and optimization in Lyon! 🤞
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Dirk Lorenz @dirque.bsky.social · 24/11/2023
Me, when I hear "A sequence gets closer and closer to its limit but can never reach it." 🧮
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Dirk Lorenz @dirque.bsky.social · 19/11/2023
Final result (plus an earlier smaller boi)
Two wooden Möbius strips
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