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A new Timestep Criterion for the Simulation of Immiscible Two-Phase Flow with IMPES Solvers
Dominik Burr, Stefan Rief, Konrad Steiner
https://arxiv.org/abs/2510.00577 https://…

A new Timestep Criterion for the Simulation of Immiscible Two-Phase Flow with IMPES Solvers
We present an iterative IMPES solver and a novel timestep criterion for the simulation of immiscible two-phase flow involving compressible fluid phases. The novel timestep criterion uses the Courant-Friedrichs-Lewy (CFL) condition and employs numerically computed velocity derivatives to adapt the timestep size, regardless of the dominant flow characteristics. The solver combined with this timestep criterion demonstrates both efficiency and robustness across a range of flow scenarios, including …

🇺🇦 #NowPlaying on KEXP's #VarietyMix
Santigold:
🎵 Disparate Youth
#Santigold
https://niksteiner.bandcamp.com/track/santigold-disparate-youth-nik-steiner-flip
https://open.spotify.com/track/7d23MhPFE9eB3U8DPRirnL

Digitale Souveränität: Nein! – Doch! – Oh!
Kommende Woche sprechen EU-Länderspitzen über digitale Souveränität. Warum Autor Falk Steiner das Thema allzu oft an eine berühmte Filmszene erinnerte.
https://www.

Sublinear Metric Steiner Forest via Maximal Independent Set
Sepideh Mahabadi, Mohammad Roghani, Jakub Tarnawski, Ali Vakilian
https://arxiv.org/abs/2510.11627 https://

Sublinear Metric Steiner Forest via Maximal Independent Set
In this work we consider the Metric Steiner Forest problem in the sublinear time model. Given a set $V$ of $n$ points in a metric space where distances are provided by means of query access to an $n\times n$ distance matrix, along with a set of $k$ terminal pairs $(s_1,t_1), \dots, (s_k,t_k)\in V\times V$, the goal is to find a minimum-weight subset of edges that connects each terminal pair. Although sublinear time algorithms have been studied for estimating the weight of a minimum spanning tre…

Randomized HyperSteiner: A Stochastic Delaunay Triangulation Heuristic for the Hyperbolic Steiner Minimal Tree
Aniss Aiman Medbouhi, Alejandro Garc\'ia-Castellanos, Giovanni Luca Marchetti, Daniel Pelt, Erik J Bekkers, Danica Kragic
https://arxiv.org/abs/2510.09328

Randomized HyperSteiner: A Stochastic Delaunay Triangulation Heuristic for the Hyperbolic Steiner Minimal Tree
We study the problem of constructing Steiner Minimal Trees (SMTs) in hyperbolic space. Exact SMT computation is NP-hard, and existing hyperbolic heuristics such as HyperSteiner are deterministic and often get trapped in locally suboptimal configurations. We introduce Randomized HyperSteiner (RHS), a stochastic Delaunay triangulation heuristic that incorporates randomness into the expansion process and refines candidate trees via Riemannian gradient descent optimization. Experiments on synthetic…

I guess it's a good first step https://toot.cafe/@tomayac/115309411832537447
But I've also been waiting for *years* (`prefers-color-scheme` was introduced in 2019), for:
- light/dark-mode `theme_color`
- light/dark-mode `background_color`
- light-dark-mode `ic…

Digitale Souveränität: Nein! – Doch! – Oh! | heise online
https://heise.de/-11079611

Digitale Souveränität: Nein! – Doch! – Oh!
Kommende Woche sprechen EU-Länderspitzen über digitale Souveränität. Warum Autor Falk Steiner das Thema allzu oft an eine berühmte Filmszene erinnerte.

„Das Digitale ist nun einmal politisch.
Genau das nicht mehr anzuerkennen, sich nicht um die technischen Gegebenheiten und ihre Folgen zu kümmern, ist ein Problem. Insbesondere für eine Regierung, die mit dem Digitalministerium und Karsten Wildberger nun endlich durch strukturelle Fachkompetenz glänzen wollte.“

Formel-1-Showdown - Norris, Max oder Piastri? Steiner legt sich fest #News #Nachrichten

Extending Thomassen's conjecture to directed graphs
Micha Christoph, Barnab\'as Janzer, Kalina Petrova, Raphael Steiner
https://arxiv.org/abs/2510.11311 https://

Extending Thomassen's conjecture to directed graphs
A famous conjecture by Thomassen from 1983 asserts that for any given $k,g\in \mathbb{N}$ there exists some $d=d(k,g)\in \mathbb{N}$ such that every graph of minimum degree at least $d$ contains a subgraph of minimum degree at least $k$ and girth at least $g$. In this paper, we initiate the systematic study of the directed analogs of Thomassen's conjecture one obtains when replacing minimum degree by minimum out-degree. Concretely, we study which digraphs $F$ are avoidable in the sense that the…

The Steiner Path Aggregation Problem
Da Qi Chen, Daniel Hathcock, D Ellis Hershkowitz, R. Ravi
https://arxiv.org/abs/2510.01392 https://arxiv.org/pdf/2510.…

The Steiner Path Aggregation Problem
In the Steiner Path Aggregation Problem, our goal is to aggregate paths in a directed network into a single arborescence without significantly disrupting the paths. In particular, we are given a directed multigraph with colored arcs, a root, and $k$ terminals, each of which has a monochromatic path to the root. Our goal is to find an arborescence in which every terminal has a path to the root, and its path does not switch colors too many times. We give an efficient algorithm that finds such a s…

A sine curve goes off to infinity, or at least the end of the blackboard.
-- Prof. Steiner

🇺🇦 #NowPlaying on #BBC6Music's #CraigCharles
Santigold:
🎵 Disparate Youth
#Santigold
https://niksteiner.bandcamp.com/track/santigold-disparate-youth-nik-steiner-flip
https://open.spotify.com/track/7d23MhPFE9eB3U8DPRirnL

Fractional Clique Decompositions of Dense Hypergraphs
Michelle Delcourt, Thomas Lesgourgues, Luke Postle
https://arxiv.org/abs/2510.07225 https://arxiv.org…

Fractional Clique Decompositions of Dense Hypergraphs
In 2014, Keevash famously proved the existence of $(n,q,r)$-Steiner systems as part of settling the Existence Conjecture of Combinatorial Designs (dating from the mid-1800s). In 2020, Glock, Kühn, and Osthus conjectured a minimum degree generalization: specifically that minimum $(r-1)$-degree at least $(1-\frac{C}{q^{r-1}})n$ suffices to guarantee that every sufficiently large $K_q^r$-divisible $r$-uniform hypergraph on $n$ vertices admits a $K_q^r$-decomposition (where $C$ is a constant that …

Randomized HyperSteiner: A Stochastic Delaunay Triangulation Heuristic for the Hyperbolic Steiner Minimal Tree
Aniss Aiman Medbouhi, Alejandro Garc\'ia-Castellanos, Giovanni Luca Marchetti, Daniel Pelt, Erik J Bekkers, Danica Kragic
https://arxiv.org/abs/2510.09328

Short circuit walks in fixed dimension
Alexander E. Black, Christian N\"obel, Raphael Steiner
https://arxiv.org/abs/2510.01916 https://arxiv.org/pdf/2…

Short circuit walks in fixed dimension
Circuit augmentation schemes are a family of combinatorial algorithms for linear programming that generalize the simplex method. To solve the linear program, they construct a so-called monotone circuit walk: They start at an initial vertex of the feasible region and traverse a discrete sequence of points on the boundary, while moving along certain allowed directions (circuits) and improving the objective function at each step until reaching an optimum. Since the existence of short circuit walks…