Tootfinder

The second part of voyages around #Szczecin: Szczecin Zdroje (= springs, as in the source of water).
We're going to find two highlights around there: Park Leśny Zdroje (= Springs Forest Park), and Puszcza Bukowa (= Beechwood), with Bukowe Zdroje (= Beech Springs) reserve. I'm going to focus on the first one today. As for Puszcza Bukowa, I'm going to say only that it's a huge forest with lots of hills, and it's kinda like going to the mountains. You can spend hours there.
As for Park Leśny Zdroje, it's got interesting landscape too. I've photographed its four most important highlights (in my opinion) for your viewing pleasure:
1. Jezioro Szmaragdowe (= Emerald Lake), named after its characteristic water color. There's a walking path across its southern and eastern shore, as well as on top of the surrounding hills. However, there's also a lot of mosquitoes there.
2. "Oko na Szczecin" (= Eye on Szczecin) overview. Unfortunately, it's been overgrown badly with surrounding shrubs. Hard not to think that "the world has moved on".
3. A #tunnel of old mine railroad. It's in a middle of a slightly overgrown path in the middle of a gully. No rails remain, though.
4. Czanowskie Wzgórze (= Chan Hill?). A nice overlook over a cliff. This one's not overgrown at all; also has no protective railings, and the ground is declining towards the cliff. Just saying, as an acrophobic person.
#hiking

Higher-dimensional grid-imprimitive block-transitive designs
Seyed Hassan Alavi, Carmen Amarra, Ashraf Daneshkhah, Alice Devillers, Cheryl E. Praeger
https://arxiv.org/abs/2404.11241

Higher-dimensional grid-imprimitive block-transitive designs
It was shown in 1989 by Delandtsheer and Doyen that, for a $2$-design with $v$ points and block size $k$, a block-transitive group of automorphisms can be point-imprimitive (that is, leave invariant a nontrivial partition of the point set) only if $v$ is small enough relative to $k$. Recently, exploiting a construction of block-transitive point-imprimitive $2$-designs given by Cameron and the last author, four of the authors studied $2$-designs admitting a block-transitive group that preserves …

What are some good (simple!) options for automagically posting RSS stuff on the Fediverse?
This works with Mastodon well enough, but I'd love a list of alternatives.
➡️ https://github.com/aserper/masto-rss

GitHub - aserper/masto-rss: A Mastodon bot that posts RSS updates to a Mastodon account
A Mastodon bot that posts RSS updates to a Mastodon account - aserper/masto-rss

Maybe agribusiness on a scale that depends on centimeter accuracy of GPS signals to guide planting equipment was a bad idea.

10. 1/2
À l'approche d'Aion survinrent de curieux déréglages, qui évoquèrent d'abord une sorte de brouillage: la coordination achoppant de manière erratique, les tâches de routine se compliquèrent. On découvrit bientôt que c'était essentiellement la communication qui était touchée et l'on soupçonna un piratage des implants sensoriels. L'hypothèse fut testée sans résultat concluant, alors que les décalages s'aggravaient et que se répandaient de nouveaux phénom…

Supersonic Acrobatic Rocket-Powered Battle-Cars: evolution of a masterpiece
I was surprised to learn that Rocket League was actually a sequel to a PS3 game by Psyonix called Supersonic Acrobatic Rocket-Powered Battle-Cars. With such a catchy title, it's hard to see why it never took off to the same extent as Rocket League did. Having said that, apparently it was downloaded on PSN over two million times, so if anything it just goes to show how I don't keep up with…

This https://arxiv.org/abs/2403.17416 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_csIR_…

AFDGCF: Adaptive Feature De-correlation Graph Collaborative Filtering for Recommendations
Collaborative filtering methods based on graph neural networks (GNNs) have witnessed significant success in recommender systems (RS), capitalizing on their ability to capture collaborative signals within intricate user-item relationships via message-passing mechanisms. However, these GNN-based RS inadvertently introduce excess linear correlation between user and item embeddings, contradicting the goal of providing personalized recommendations. While existing research predominantly ascribes this…

10. 1/2
À l'approche d'Aion survinrent de curieux déréglages, qui évoquèrent d'abord une sorte de brouillage: la coordination achoppant de manière erratique, les tâches de routine se compliquèrent. On découvrit bientôt que c'était essentiellement la communication qui était touchée et l'on soupçonna un piratage des implants sensoriels. L'hypothèse fut testée sans résultat concluant, alors que les décalages s'aggravaient et que se répandaient de nouveaux phénom…

This https://arxiv.org/abs/2310.08880 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

On the sum of the first two largest signless Laplacian eigenvalues of a graph
For a graph $G$, let $S_2(G)$ be the sum of the first two largest signless Laplacian eigenvalues of $G$, and $f(G)=e(G)+3-S_2(G)$. Oliveira, Lima, Rama and Carvalho conjectured that $K^+_{1,n-1}$ (the star graph with an additional edge) is the unique graph with minimum value of $f(G)$ on $n$ vertices. In this paper, we prove this conjecture, which also confirm a conjecture for the upper bound of $S_2(G)$ proposed by Ashraf et al.

This https://arxiv.org/abs/2310.08880 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

On the sum of the first two largest signless Laplacian eigenvalues of a graph
For a graph $G$, let $S_2(G)$ be the sum of the first two largest signless Laplacian eigenvalues of $G$, and $f(G)=e(G)+3-S_2(G)$. Oliveira, Lima, Rama and Carvalho conjectured that $K^+_{1,n-1}$ (the star graph with an additional edge) is the unique graph with minimum value of $f(G)$ on $n$ vertices. In this paper, we prove this conjecture, which also confirm a conjecture for the upper bound of $S_2(G)$ proposed by Ashraf et al.